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MCAP Manual - Salient Sciences

1. Abort g 6029 Hz Atten Figure 4 51 Hi Res Graphic Define Edit Region Now draw in the new portion of the filter curve using mouse clicks as in Step 4 above roughly as shown below Figure 4 52 CGAY Page 90 9 10 Abort g 5643 Hz Atten Figure 4 52 Hi Res Edit In Progress Complete drawing the new portion of the filter curve as shown below Figure 4 53 by drawing points all the way to the right edge of the edit region New Edit Normalize Store Recall Filter In aa 4271 Hz Atten Figure 4 53 Completed Hi Res Graphic Edit When you have drawn the last point must be at or beyond the right edge of the edit region the mouse cursor will change to an hourglass shape for a few seconds while the filter is being recalculated When the calculations are complete the mouse cursor and the buttons in the Hi Res Graphic control window will return to normal appearance Normalizing the filter places the highest point on the filter curve at 0 dB Doing so minimizes loss in the filter and preserves system dynamic range Now normalize the filter curve to OdB by clicking the Normalize button You should see the mouse cursor change to the hourglass shape for a few seconds when the normalization calculations are complete the filter shape should appear as follows Figure 4 54 CAY Page 91 Free n Store Recall Filter In OK 2127 Hz Atten Figure 4 54 Normalized Hi Res Graphic
2. ccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeneneaaees 7 Figure 2 2 Master Control Panel E 8 Figure 2 3 Firmware Upgrade Wizard con 9 Figure 3 1 MCAP Connection Diagram EEN 11 Figure 3 2 Fast Start File Pulldown Menu ees 12 Figure 3 3 Fast Start Recall Setup Window see 12 Figure 3 4 Tutorial Master Control Panel 14 Figure 3 5 Tutorial Limiter Setup Wumdow en 16 Figure 3 6 Tutorial AGC Setup VWumdow 17 Figure 3 7 Tutorial Filter Selection Window and Combo Box 18 Figure 3 8 Tutorial 1CH Adaptive Filter Control WindOW 0 eeeeeeeseeeeeeeeneeeeeeeeaes 18 Figure 3 9 Tutorial Lowpass Filter Control Wimdow ssssssssssnsesssessnrnrnnnssserrrrrnnnnnesee 19 Figure 3 10 Tutorial Equalizer Selection Wmdow ssssssssssessssssssssrrnrrressserrrrrnnnnnesee 20 Figure 3 11 Tutorial 20 Band Graphic Equalizer Control Wmdow ssssesssssssseeneeeee 21 Figure 3 12 Tutorial Store 20 Band Graphic Equalizer Window sssseseesessssesenneeeene 21 Figure 3 13 Tutorial Recall 20 Band Graphic Equalizer WindoW cceeceeeeeeeees 23 Figure 3 14 Tutorial Spectrum Analyzer Wmmdow 24 Figure 3 15 Tutorial Display Select Menu eeeeeeeeececcceeeeeeeeeeneeeeeeeeeeeeteeetenseeeees 25 Figure 3 16 Tutorial File Pulldown Men 26 Figure 3 17 Tutorial Save Setup File Window AEN 26 Figure 3 18 Tutorial Store in File Name Text Box 27 Figure 3 19 Tutorial Report Generator Pulldown Mem 28 Figure 4 1 Master Contr
3. m Transition Slope Stopband Attenuation Lower 1 dB Octave Upper 1 dB Octave U cly 4 i Figure 4 22 Bandstop Filter Control Window Specifies frequency in Hertz above which no signals are attenuated Frequencies between this cutoff and the Lower Cutoff Frequency are attenuated Minimum Upper Cutoff Frequency is 10 Hz above the Lower Cutoff Frequency while the maximum Upper Cutoff Frequency depends upon the System Bandwidth setting Upper Cutoff Frequency can be adjusted in 1 Hz steps NOTE The Upper Cutoff Frequency can never be set lower than 10 Hz above the Lower Cutoff Frequency Specifies slope at which frequencies above the Lower Cutoff Frequency and below the Upper Cutoff Frequency are attenuated in dB per octave Sharpest attenuation occurs when Transition Slope is set to maximum while gentlest attenuation occurs when Transition Slope is set to minimum Note that the indicated value changes depending upon Cutoff Frequency System Bandwidth Configuration and Number DSP Stages settings Also note that the Lower and Upper Transition Slopes always have different values this is because the frequency width of an octave is proportional to Cutoff Frequency Specifies amount in dB by which frequencies above the Lower Cutoff Frequency and below the Upper Cutoff Frequency are attenuated Stopband attenuation is adjustable from 10dB to 60dB in 1 dB steps G Page 59 Filter Button Used to switch
4. CA Page 43 4 3 2 Equalizer Selection Window The last DSP stage is always an Equalizer stage Clicking the Select button for any Equalizer block not a Filter block causes the following window Figure 4 12 to appear Click the mouse on the desired equalizer type then click on OK or simply double click the desired equalizer type to select it for the current Equalizer block Alternately the equalizer select combo box can be used in the same manner as with the Filter blocks Clicking the Control button for any Equalizer block causes the control window for the selected equalizer mode to appear See Section 4 5 DSP Equalizer Control Windows for detailed information on control windows for each equalizer mode VW E Choose Equalizer Type Spectral Graphic Dual Parametric Compressor Expander Figure 4 12 Equalizer Selection Window 4 4 DSP Filter Control Windows This section provides detailed description of the control window for each filter mode For any DSP Filter block the control window for the selected filter is accessed by clicking on the Control button CGAY Page 44 4 4 1 Ref Canceller formerly 2CH Adaptive Filter Application The Reference Canceller filter is used to automatically cancel from the filter inout any audio which matches the selected Reference input For example suppose the LEFT PRI MAIN INPUT is microphone audio with desired voices masked by radio or TV sound the radio TV interference can be
5. ccccceeeeeeeeeeeeeeeeeeeeeeeeeteeeeeeees 60 Figure 4 24 Comb Filter Control VWumdow 61 Figure 4 25 Comb Filter Graphical Description sssssessssnnrneeeseeerrrrnnrreneserrrrnnnnneeeee 63 Figure 4 26 Inverse Comb Filter Control Wmdow ssssssssssennneeesseessnernrnnnnsserrrrennnnneeeee 64 Figure 4 27 Notch Filter Control Wmmdow A 66 Figure 4 28 Notch Filter Graphical Description sesssessssennnneeeseeernrnrnrnneeerrrnrnnnnneeeee 67 Figure 4 29 Multiple Notch Filter Control Window eee ceeeeeeeneeeeeeeeneeeeeeesneeeeeeneaaes 68 Figure 4 30 Multiple Notch Filter Graphical Description 0 eeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 69 Figure 4 31 Slot Filter Control Wumdow sssssssssseeneesnsssssrrnnrrrresseerrrnnnnnnnnseerrrnrnnnnnenent 70 Figure 4 32 Slot Filter Graphical Description EE 71 Figure 4 33 Multiple Slot Filter Control Wmdow sssseeeeesssnennnnneesesesnennrrrnssserrrrnnnnnnesee 72 Figure 4 34 Multiple Slot Filter Graphical Description 73 Figure 4 35 Basic Process of Spectral Inverse Filter cc ceeesseeneeeeesseeeeesesseees 75 Figure 4 36 SIF Control Window When Equalize Voice Gelected 76 Figure 4 37 SIF Control Window When Attack Noise Geleched 78 Figure 4 38 Spectral Inverse Filter Store Window 0 eeeeeeeeeeeeeeeeeeeeneeeeeseneeeeeeeneaaes 80 Figure 4 39 Spectral Inverse Filter Recall Window sseeeceesesseeseeeeesseeeeeeenseees 80 Figure 4 40 EQ Voic
6. listening level A Mute check box allows the user to quickly toggle the headphone outputs on and off when necessary If however panel control of the headphones is preferred the Enable Panel Controls check box can be selected to enable the VOLUME MONITOR and SELECT controls in the HEADPHONE MONITORING block on the MCAP front panel 4 3 DSP Processor Selection 4 3 1 Filter Selection Window Clicking the Select button in any Filter block not an Equalizer block causes the following window Figure 4 10 to appear G Page 42 x Choose Filter Type Notch Multiple Notch Slot Multiple Slot Spectral Inverse Hi Res Graphic 20 Band Graphic Tri Parametric Inverse Comb Compressor Expander Figure 4 10 Filter Selection Window Click the mouse on the desired filter type then click on OK or simply double click the desired filter type to select it for the current Filter block Another way of selecting the filter is by using the filter select combo box shown in Figure 4 11 To select the filter first click on the small arrow to the right of the combo box and then using the drop down menu that appears Click on the desired filter Left Filter 1 Figure 4 11 Filter Select Combo Box Clicking the Control button in any Filter block causes the control window for the selected filter type to appear See Section 4 4 DSP Filter Control Windows for detailed information on control windows for each filter type
7. AGC Out ES Figure 3 6 Tutorial AGC Setup Window Use the mouse to set the Release Time to 200 milliseconds and the Maximum Gain to 20dB as shown in Figure 3 6 Make sure the AGC button indicates AGC Out Click on OK when done Reduce the input level until the Output Level Bargraphs indicate a peak signal level of approximately 36dB Switch the AGC in and out by clicking on the AGC button in the Output Levels block You should notice the output level bargraphs slowly increase to approximately 18dB indicated level and the audio level as heard through the headphones dramatically increase whenever the button indicates AGC In The AGC attempts to make the Output Level constant and is useful in near party far party situations Restore the button to the AGC Out indication and restore the input levels to normal Click on the Select button in the Filter 1 block A window similar to the one in Figure 3 7 will appear Use the mouse to click on 1CH Adaptive then OK The Filter 1 block should now indicate that the selected mode is 1CH Adaptive Alternately click the down arrow button on the Filter 1 combo box to select 1CH Adaptive from the drop down menu Double clicking the desired filter mode will avoid having to click the OK button CAY Page 17 Ea Choose Filter Type Ref Canceller 1CH Adaptive Lowpass Highpass Bandpass Bandstop Comb Notch Multiple Notch Slot Multiple Slot Spectr
8. gt 90 dB AES EBU professional format transmitter and receiver with XLR connectors Simultaneous analog and digital outputs CAY Page 136 Digital Processing Digital Filters Limiter Microprocessor Digital Filter Processors Memory Computer Interface Construction Packaging Power 32 44 1 and 48 kHz data rates 8192 tap dynamically configurable adaptive fixed digital filter array Two dedicated 256 tap FIR equalizers Four input and two output 255 order linear phase digital highpass rumble filters Microprocessor controlled Adjustable release time and threshold Four TMS320C50 20 MHz allocated to control analog digital conversion real time signal processing filter synthesis and control and real time FFT spectral analysis Forty three DSP56200 FIR filter microprocessors Two 64k x 8 boot EPROMs four 32k x 16 program RAMs 32k x 16 signal processing delay RAM 32k x 16 FFT RAM 512k x 8 flash memory for program and coefficient storage 4 megabyte DRAM for input signal delays six 1024 x 8 FIFO communications buffers Dual RS232 serial interfaces for system control and dedicated spectrum analyzer display 9600 to 38 400 selectable baud transfer rate 1 75 H x 19 0 W x 15 D 10 Ibs Rugged aluminum enclosure Optional rack mount kit available 85 VAC to 264 VAC 47 to 440 Hz auto switching power supply built in CGAY Page 137 Host Computer e Optional 12 VDC power supply availab
9. i external processor communication established GI PC is unable to establish a link with the a MCAP on the selected COM port at the selected Baud Rate Master Control Panel software is currently dialing a remote MCAP The Master Control Panel software is configured for a Remote MCAP connection and is currently hung up KI The Master Control Panel is connected to Sey a remote MCAP via the PassThru exe software CAY Page 34 4 2 Input and Output Processors 4 2 1 Input Path Delay Lines Application In field enhancement operations there can often be a large delay difference between signals to be processed and the Reference signal to be used for a particular reference canceller formerly 2CH Adaptive filter stage particularly if a satellite feed is used for either channel Thus it is often necessary to place compensation delays on one or more of the input channels In the past separate signal delay units were required to accomplish this on the MCAP however this capability is built in Depending on the System Bandwidth selected from 0 to a maximum of 14563 to 72818 milliseconds of delay can be placed on any of the input channels The Headphone Monitoring feature allows the user to roughly time align selected input pairs by ear Clicking on the Path Delay button will cause the Path Delay Window shown in Figure 4 3 to appear Specify front end delay for each input signal Listen through headphones to audibly
10. 312 5 Hz Width 3448 3 Hz AA A ge E Vike A B 0 O S T C U T NN lt E E SSES Ze E Bee Es am EE e le GE Ee De DEE ee ee ees E es W ees EE E P Eed il Center Frequency 1 kHz Figure 4 56 Graphical Representation of a Parametric Filter 4 4 17 Limiter Compressor Expander Application The LCE Limiter Compressor Expander is a three section dynamic signal level processor recommended for advanced users only Dynamic signal level processing enables the user to manipulate the overall dynamic range of a signal generally to correct for near party far party and or quiet talker scenarios CGAY Page 95 The three types of level processing available three sections in the MCAP are limiting compression and expansion Unlike an analog implementation of this process the MCAP digital implementation is substantially easier to set up and operate and is far more accurate All matching of amplifier gains is carried out automatically by the MCAP s microprocessor Logarithmic level conversions are carried out precisely in real time These dynamic processes modify the amplitude of the signal using a variable gain digital amplifier The amplitude is a rectified and smoothed version of the signal wave form as measured by a real time digital envelope detector The envelope detector is controlled by its Attack Time and Release Time which are adjustable Normally a fast attack time and sl
11. 60dB ROSI B0dB GER 0e 30dB 4c 0000 90 dB 100dB Output 200 80dB 70dB 60dB 50dB 40dB 30dB 20dB 10dB Op 7 Ti TTT Fiten OK Level Figure 4 57 Limiter Compressor Expander Control Window Description of operation Six different parameters are adjustable on the LCE Control Window e The Expansion Ratio can be adjusted through a range of 1 1 to 1 100 by using the scroll buttons beside its text entry box by entering the value in its text entry box or by clicking on the Expansion Ratio Curve using the CGAY Page 97 mouse pointer and adjusting it to the desired value NOTE Only the portion of the ratio to the right of the colon is specified e The Compression Threshold can be adjusted through a range of 90dB to OaB by using the scroll buttons beside its text entry box by entering the value in its text entry box or by clicking on the Compression Threshold line using the mouse pointer and adjusting it to the desired value e The Compression Ratio can be adjusted through a range of 1 1 to 100 1 by using the scroll buttons beside its text entry box by entering the value in its text entry box or by clicking on the Compression Ratio Curve using the mouse pointer and adjusting it to the desired value NOTE Only the portion of the ratio to the left of the colon is specified e The Limit Threshold can be adjusted through a range of 90dB to 0dB by using the scroll buttons beside its tex
12. The minimum number of coefficients that can be displayed is 32 while the maximum number of coefficients varies according to the actual size of the Filter To display all the coefficients in a Filter stage click on All Used to specify the vertical scale factor to be used when displaying coefficients Coefficients may be scaled from 1X no scaling to a maximum of 200X If the scaled coefficient exceeds the maximum vertical display limits it will be clipped prior to display This clipping does not affect signal processing Marker Block Used to move the vertical red marker in the Coefficient Display area allowing Time and Value readout of any coefficient that is displayed CGAY Page 109 Coefficient Display Hide Controls Close Button The horizontal scroll bar is used to precisely place the marker at the desired filter coefficient Make coarse adjustments to marker position by dragging the scroll box slider with the mouse Click on the scroll bar or scroll arrows at either end of the scroll bar to make fine adjustments The Coefficient Display area will pan or shift left or right whenever the marker selects a coefficient that is outside the displayed area Clicking the Find Peak button instantly moves the marker to the largest coefficient in the filter panning the display if necessary For faster placement of the marker click the mouse cursor on the desired point in the Coefficient Display area Click on the left
13. To draw the new filter curve you will need to carefully click the mouse cursor on points within the filter display area which correspond to the desired attenuations at the desired frequencies While the mouse pointer is moved across the graph the Freq and Atten readouts will be updated as the mouse is moved you can use this feature to place points in the filter curve at exact frequencies and attenuations A line segment will be drawn wherever the mouse pointer is moved in the graph For this example placing points at precise frequencies and attenuations is not required draw the curve approximately as shown in Figure 4 48 using mouse clicks Note that the very first click always sets the 0 Hz attenuation starting point Hint To advance the frequency a single step move the cursor to the left of the last frequency position and click the mouse The curve will advance one frequency step at the specified attenuation CAY Page 88 Abort 3832 Hz Alten Figure 4 48 Hi Res Graphic Draw in Progress 5 Complete drawing the filter curve as shown below Figure 4 49 by drawing points all the way to the right edge of the filter display area Edit Normalize Store Recall Filter In 141 Hz Atten ad Figure 4 49 Completed Hi Res Graphic Draw When you have drawn the last point must be at or beyond the right edge of the filter display area the mouse cursor will change to an hourglass shape for a few seconds while the
14. several sets of Limits build the SIFs Store the filters and Recall and compare in an A B fashion In the Attack Noise Operation bracket the noise band surgically with these Limits If there are several disjoint noise bands series additional SIFs The MCAP will series up to four The audio outside those limits is unfiltered Range and Gain SIF is a spectral attenuator The spectral peaks are pressed down toward the spectral valleys The amount of reduction is limited by the Range scroll bar If however all peaks are reduced to the owest valley no more reduction takes place CGAY Page 83 ie x Analyzer Filter Operation EQ Range Gain Sarl Run Sam Range 30 dB Build OdB C Equalize Voice 4 gt es CG Attack Noise Gain 0 dB Filter In 64 E F d i Store Lower Voice Limit r Upper Voice Limit r Output Shape j 281 Hz 3164 Hz Flat C Voice Recall Al Pink ox Figure 4 43 Attack Noise operation Attack Range set to 30dB For example if the distance from the highest peak to the lowest valley between the Upper and Lower Limits is 30dB the maximum range actually used will be 30dB even if the scroll bar is set to a larger Range Normally a Range of 10 20dB is adequate as attacking the stronger spectral peaks will provide the necessary enhancement Go gently at first and compare several SIFs with different Ranges The Store and Recall memories are useful in saving candidate filter soluti
15. 2kHz C 8 kHz cow owp Left Right oL OL oL oL 5 Se G 5 4kHz C 11 Mis Select Control Select Control E o o D C 65kHzC 16 kHz Filter In Filter In o 3 3 3 3 Left Filter 2 Right Filter2 F z a r Configuration gh s 3 3 3 3 12 12 12 C Mono Select Control Select Control 12 Ai Ji RS C Stereo Linked Filter In Filter In Ra geg SE Adapt Clear Adapt Clear a 24 24 24 Stereo Indep 24 zA a m Left Filter 3 Right Filter 3 a E ae Number DSP Stages FF Adaptive 339 48 48 48 e e Select Control Select Control 48 57 5T 57 C3 Filter In Filter Out Ka 63 63 63 a Adapt Clear Adapt Clear ae 23 ay 29 oa OHPF In OHPF Setup Clear All AGC In Adapt Enabled AGC Setup Processor In Left seg nr Right Ze E Headphones Limiter Out Path Delay Out Path Limiter Out Path Delay 20 Band Graphic Spectral Graphic Coefficient Display Select BE Select e ES Limiter Setup IHPF In Setup Spectrum Analyzer Equalizer In Equalizer In E CLO Figure 2 2 Master Control Panel If an error message is displayed it is possible that the software is not configured for the correct COM port software defaults to COM2 If you know to which COM port the MCAP external processor is connected configure the MCAP Master Control program for the correct COM port by following the procedure in Section 6 1 The MCAP system should now be installed and ready to run 2 3 Fi
16. Down Menu Figure 8 4 shows the changes to the Main Screen when Configure is selected This new menu allows the remote user to customize the program The remote user can select the correct settings for the MCAP and MODEM serial communication connections Com Port Com through Com4 and baud rate 1200 through 38400 Clicking on Advanced Session Setup will pop up the screen in Figure 8 5 This screen should not need to be modified if the remote MODEM is compatible with the Hayes AT Command Set It is provided to allow any additional commands to be sent to the MODEM If the MODEM does not appear to be functioning properly click on this menu option to bring up the screen Click on Default to set the screen to the factory defaults then click on OK to exit and use the new settings Clicking on Set Entry Password in the Configure Drop Down Menu will pop up the screen in Figure 8 6 This screen allows the remote operator set the password that is CGAY Page 130 used to authenticate the Base Location when it attempts to link up to the remote MCAP The password is any collection of from 6 to 25 characters The program automatically converts lower case letters to upper case Advanced Session Setup Modem Initialization Enter for RETURN Modem Response Figure 8 5 Advanced Session Setup Screen Remember that both the base PC and remote PC have to agree on the same sequence of characters If the password box contains two words separated by a
17. Filter This completes the Hi Res Graphic Filter mini tutorial 4 4 15 20 Band Graphic Filter Application The 20 band Graphic Filter is an easy to use linear phase FIR digital filter that is used to reshape the spectrum of the signal Reshaping is accomplished with twenty vertical scroll bars also called slider controls which adjust the attenuation of each frequency band These controls are very similar to the slider controls of analog graphic equalizers found on many consumer stereo systems and thus should be very familiar to even the novice user However unlike analog graphic equalizers this digital equalizer has some very powerful additional capabilities For example the Normalize button allows the user to instantly move all slider controls up until the top slider is at 0dB The Make All OdB button instantly sets all the sliders to OdB The All Down 1dB button instantly moves all sliders Down 1dB None of these functions is available in an analog graphic equalizer Notice also that the 20 sliders are spread across the selected Bandwidth and that the frequency spacing is optimized for voice processing Additionally since a computer with a disk drive operates the equalizer a Store and Recall capability is available This allows the user to store commonly used slider configurations in disk memories so that they can be instantly recalled later whenever they are needed without having to manually adjust the slider controls Descriptio
18. For speech processing applications settings of 3 2kHz to 6 5kHz work best For wider bandwidth signals applications 8 0kKHz to 16kHz is recommended NOTE This is completely independent of the sample rates used for digial inpuVoutput when digital I O is used Selects mono or stereo filter configurations Mono configuration allows the user to enhance a single input signal with as many as nine successive stages of digital signal processing Stereo Linked configuration allows the user to process two input signals simultaneously with as many as five stages of digital signal processing each stage is identical for both the left and right channels Stereo Indep configuration is the same as Stereo Linked except that the processing stages may be set up differently for the left and right channels Changing any of these settings will automatically clear all 2CH Adaptive 1CH Adaptive Multiple Notch Multiple Slot Spectral Inverse and Hi Res Graphic Filters Ibid CAY Page 32 Number DSP Stages Box Filter Box es Equalizer Box es Clear All Button Adapt Button Processor Button Ibid Selects the number of DSP Digital Signal Processing processing stages that are to be used DSP stages consist of both Filter stages and Equalizer stages At least two stages are always available 1 DSP Filter 1 DSP Equalizer but depending on System Bandwidth and Configuration as many as nine stages can be available U
19. MCAP external processor from the Stand Alone memories please consult Section 5 0 G Page 115 4 9 5 Generating Setup Reports The MCAP Master Control program has a ReportGenerator feature which allows hardcopy printouts of MCAP control settings to be generated This is useful when the enhancement procedure needs to be documented To access this feature click on ReportGenerator in the Master Control menu bar The following pulldown menu Figure 4 68 will be displayed ReportGenerator Print Report To Printer Print Report To Eile Append Report To File How To Print Screens Figure 4 68 ReportGenerator Pulldown Menu Clicking the Print Report to File option prints the control settings to a user specified ASCII text file which could later be imported to a word processor editing All previous contents of the specified file will be overwritten However this option is limited since no graphics can be stored in a text file If you wish to transfer graphical information to a word processor click on How to Print Screens for instructions Clicking the Append Print Report to File option causes the printed control settings to be tacked on to the end of any existing text file without overwriting the previous contents As with the Print Report to File option no graphics can be stored Clicking the Print Report to Printer option sends all control settings including graphs for certain Filter and Equalizer modes to the Windows Print Mana
20. Notch Freq 1 16 Specifies frequency in Hertz which is to be removed from the input audio by each of the 16 notches Minimum Notch Freq is 1 Hz while maximum Notch Freq depends upon the System Bandwidth setting Set Notch Freq to Out scroll box in full left position if the notch is not desired Notch Freq is adjustable in 1 Hz steps Notch Width Specifies width in Hertz for each of the 16 notches Minimum and 1 16 maximum Notch Widths and adjustment resolution depend upon the System Bandwidth setting Build Button Causes the FIR filter coefficients for the Multiple Notch filter to be calculated and downloaded to the MCAP external processor for implementation While this is occurring an hourglass mouse cursor will appear NOTE You must click the Build button after any Notch Freq or Notch Width is changed in order for the change to take effect You must also click the Build button after any change in System Bandwidth Configuration or Number DSP Stages in order to rebuild the filter C Page 68 Destroy Button Control Button Filter Button Clears all Notch Freq and Notch Width settings for all 16 notches and restores the Multiple Notch filter coefficients to an allpass filter no notches The Multiple Notch control window is only capable of displaying the settings for eight notches at a time Notches 1 8 or Notches 9 16 may be displayed Click on the Control button to toggle between Control 1 8 Notches 1 8 display
21. Out You should notice a reduction in background noise whenever the button indicates Filter In Press the Clear button to cause Filter 1 to readapt to the input signal Restore the Filter button to the Filter Out indication and click on OK to exit the 1CH Adaptive Filter Control Window Click on the Control button in the Filter 2 block The window in Figure 3 9 will appear LC LS Cutoff Frequency Stopband Attenuation 3500 Hz 60 dB Zam IS Transition Slope Filter Out 1365 dB Octave yf 3 Figure 3 9 Tutorial Lowpass Filter Control Window This is the Lowpass Filter Control Window It is used to select Cutoff Frequency Stopband Attenuation and Transition Slope Use the mouse to set all controls to match the settings shown in Figure 3 9 Do not click on the OK button at this time Listen to the filter OUTPUT through your headphones Note the effect on the signal as the Filter button is toggled between Filter In and Filter Out You should notice a dramatic reduction in high frequency sound whenever the button indicates Filter In Scroll bars are used throughout the MCAP to adjust various filter parameters Drag the scroll box slider or click within the scroll bar to make coarse adjustments Click on the scroll arrows on either end of the scroll bar to make fine adjustments CGAY Page 19 29 30 31 32 33 34 Try adjusting the Cutoff Frequency control to various settings as the Cutoff Frequency
22. PC and remote MCAP transferring information in both directions between the two devices After the Base Location operator is finished the operator exits the MCAP Master Control Software This will cause the base MODEM to hang up and break the link Once PASSTHRU at the Remote Location determines that no activity is occurring on the link it will reset itself for the next caller The PASSTHRU program is designed to operate automatically The program handles all the overhead of maintaining the link on the Remote Location side of the system The operator is not needed during normal operation only if a major error is detected An example of a major error would be if no MCAP were connected to the PC Once the program is operating it constantly monitors the remote phone line and valid users to dial in and link to the remote MCAP Any break in the link will force the program to hang up the phone and prepare for another caller 8 2 Program Features and Options This section illustrates the various options that are available in the PASSTHRU program After a one time initialization of the remote PC two mouse clicks are all that are required to start the program from Windows and allow the Base Location to access the remote MCAP NOTE It is strongly recommended that a shortcut be made to the PASSTHRU program in the Start Menu so that in the event of a power failure it can be quickly re launched 8 2 1 PASSTHRU Program Icon Figure 8 2 show
23. Viewing DSP Displays Click on View to access the Display Select window shown in Figure 4 61 on page 103 See Section 4 6 2 for further details 4 9 4 Storing Setups to External Processor Stand Alone Memories Application The MCAP external processor has the capability to store up to four enhancement setups internally in nonvolatile Stand Alone memories allowing the external processor to be operated in those setups without needing to be connected to a PC This makes it possible to store sophisticated enhancement setups in one or more external processors in the laboratory then use them as portable field processors which have simple controls that can be operated by anyone Thus with this feature the complete capabilities of the enhancement laboratory and the expertise of the laboratory personnel can be extended to field operations For all memories the function of the AUX switch on the external processor front panel can be specified Store a setup in a nonvolatile memory as follows 1 Adjust all Master Control Filter and Equalizer settings as desired to achieve the desired enhancement setup This may also be accomplished using the Open Setup File feature described in Section 4 9 2 It is strongly suggested that you store this enhancement setup to disk using the Save Setup File feature described in Section 4 9 1 NOTE There is no way for the Master Control program to retrieve from the MCAP and interpret the settings and coefficients st
24. Y Enable Panel Input Level Controls v Enable Panel Headphone Controls Figure 6 2 BaudRate Selection Menu CAS Page 122 After storing the new baud rate by exiting the MCAP Master Control program test the new baud rate as follows a Switch on the MCAP external processor Make sure that the OPERATION switch on the external processor is set to REMOTE and that the RS232 cable is properly connected between the external processor and the PC b Double click on the MCAP Master Control icon to run the program C Allow several seconds for the program to load and to initialize the external processor The Status Icon should display the connected image d Connect a line level audio signal to either the LEFT or the RIGHT ANALOG MAIN INPUTS BNC jack and adjust the input level so that the tricolor level LEDs indicate GREEN If the Input Level bargraphs on the MCAP Master Control screen properly respond to the input signal then the hardware and software are correctly configured for the new baud rate 6 3 Customizing Screen Colors Many of the MCAP Master Control program screen colors are set by the Windows environment To change these colors first open the Control Panel by clicking on the Start button on the Taskbar then clicking on the Settings menu option There you will see the Control Panel icon Double click on the Display icon and select the Appearance tab In this window you can select a Scheme from the list box and view the appearanc
25. align References with Primary Pri fe 33 milliseconds D E 2250 00 4 all gt 4 b gt Refi milliseconds aa Ref2 26 00 a Ref3 fi 2 00 milliseconds i milliseconds l PrfRefl ene C Pri Ref2 E ran C PrifRef3 Mute Zero All Delays Figure 4 2 Path Delay Window CA Page 35 All Path Delays are specified in milliseconds and can be adjusted in increments as fine as eight samples 0 2 to 1 1 milliseconds depending upon selected System Bandwidth Each channel has both a text box and a slider control for specifying delay Use the text box to type in the desired delay directly or use the slider control to adjust the delay by ear Make coarse delay adjustments by either dragging the slider scroll box or clicking on the scroll bar area to the left or right of the scroll box The left and right arrow buttons on either end of the slider controls can be used for fine eight sample delay adjustment At any time the Zero All Delays button can be clicked to set all the Path Delay settings to zero no delay The Monitor controls are used to select which input signal pair is to be aurally time aligned using the headphones Pri Ref1 Pri Ref2 or Pri Ref3 The Volume and Mute controls are provided for the operator s listening convenience Note Whenever the Path Delay Window is opened the headphone outputs automatically switch to monitoring the specified input pair This does not affect the M
26. block Therefore the user should strive to minimize the sizes of all adaptive filters used in order to maximize the number of available filter stages Used to set the rate at which the adaptive filter adapts to changing signal conditions Mathematically known as Mut A Mu of 1 x 2 provides very slow adaptation while a Mu of 5884 x 2 provides fastest adaptation Warning Be careful when using Adapt Rates larger than 256x2 as the instability could cause the filter to crash Larger adapt rates should be used with changing noises such as music whereas smaller adapt rates are acceptable for stable tones and reverberations Larger adapt rates sometimes affect voice quality as the filter may attack sustained vowel sounds Sets the number of samples in the prediction span delay line Prediction span is indicated both in samples and in milliseconds and can be adjusted from 1 to 4096 samples or higher depending upon maximum filter size Shorter prediction spans allow maximum noise removal while longer prediction spans preserve voice naturalness and quality A prediction span of 2 or 3 samples is normally recommended Selects Auto matic or Fixed adaptation rate Auto is recommended When Fixed is selected the specified Adapt Rate Mu is applied to the filter at all times However when Auto is selected the specified Adapt Rate is continuously rescaled depending upon the input signal level Overall convergence rate is faster with Aut
27. comfortable listening level Select the desired Stand Alone memory by switching the MODE switch to 1 2 3 or 4 Initially set the front panel ADAPT FREEZE PROCESS BYPASS and AUX OFF switches to ADAPT PROCESS and AUX all switches up While listening with the stereo headphones switch the MONITOR switch between MAIN INPUTS and OUTPUTS to hear the difference between the original and processed audio respectively To monitor the extra REFERENCE signals switch the MONITOR switch to REF INPUTS You may make the following adjustments to the processor at any time 1 To freeze all adaptive filters in the process switch the ADAPT FREEZE switch to FREEZE To allow the adaptive filters to adapt to changing signals switch to ADAPT CGAY Page 118 To bypass all digital filters allowing the original unfiltered audio to pass through to the LEFT and RIGHT ANALOG MAIN OUTPUTS BNCs and the DIGITAL MAIN OUTPUTS XLR switch the PROCESS BYPASS switch to BYPASS To filter the audio switch to PROCESS The AUX switch is programmed to have one of the following functions when switched to AUX a No effect at all default b Input Limiter IN C Input HPF IN d Output AGC IN e Output HPF IN f Right channel Adapt Freeze ADAPT FREEZE switch used for Left channel only g Filter 2 8 Adapt Freeze ADAPT FREEZE switch used for Filter1 only When switched to OFF the AUX switch always has no effect on the signal To clear all filters
28. filter processors which perform digital highpass rumble filtering on all inputs pre process and all outputs post process with adjustable cutoff e Four general purpose microprocessors which execute special DSP software implement the dual FFT spectrum analyzer communicate with the PC via RS232 and provide system control Programmable gain input amplifiers allow input levels to be adjusted either on screen when operating under PC CONTROL or by front panel knobs when operating STAND ALONE Microprocessor controlled limiters are provided on all four analog inputs to prevent overload Analog to digital conversion is performed by two stereo sigma delta 16 bit converters which 64X oversample the incoming analog audio Digital to analog conversion is performed by two stereo delta sigma 16 bit converters one for line output one for headphone output which 64X oversample the output audio The base sample rate is adjustable from 7 2 kHz 3 2 kHz bandwidth to 36 kHz 16 kHz bandwidth All sample rates are exact multiples of 50 Hz and 60 Hz allowing maximum filter performance at harmonics of these frequencies CAY Page 2 Digital AGCs are provided to compensate for near party far party voice level differences Four stand alone nonvolatile memories are provided for onboard storage and recall of filter setups created by the MCAP Master Control Program This allows the external processor to be operated in any of four previously stored
29. inverse filter response rolls up to OdB no attenuation outside the frequency limits EQ or Attack Gain specifies the digital boost to be applied to the entire spectral inverse filter curve Normally Gain is applied in the CGAY Page 77 Lower and Upper Frequency Limits 7 Analyzer Num Ave Lower Noise Limit Equalize Voice mode the gain is usually 0 dB in the Attack Noise mode This boost is necessary to make up for the volume reduction performed by the inverse filter Gain should be initially set to approximately 50 percent of the Range setting If filter output is distorted reduce Gain setting and re Build the filter if filter output level is too low try increasing the Gain setting Filter Operation Attack Range Gain s Run t fell Range 13 dB Build OdB ng E C Equalize Voice af J gt L Store m Upper Noise Limit Output Shape KS a ES a Attack Noise m d 16 7 Filter In 1758 Hz 2971 Hz Flat Voice Recall EL Sait C Pink ox 8086 Hz Figure 4 37 SIF Control Window When Attack Noise Selected For EQ Voice operation specifies Lower Voice Limit and Upper Voice Limit These are the lower and upper frequency limits over which the input voice audio is equalized Audio outside these limits is rolled off and ultimately attenuated by 40dB A Lower Limit above 300 Hz and an Upper Limit below 3000 Hz is not recommended as voice intelligibility may suffer For Attack Noise
30. is increased you should hear high frequency sounds increase and as Cutoff Frequency is reduced high frequency sounds will be reduced Click on OK to exit the Lowpass Filter Control Window Click on the Filter button in the Filter 2 block until it indicates Filter Out Click on the Equalizer button in the Equalizer block until it indicates Equalizer In Click on the Select button in the Equalizer block The window in Figure 3 10 will appear VW Ea Choose Equalizer Type Spectral Graphic Dual Parametric Compressor Expander Figure 3 10 Tutorial Equalizer Selection Window Use the mouse to click try double clicking to avoid clicking on OK on 20 Band Graphic The Equalizer block should now indicate that the selected mode is 20 Band Graphic Click on the Control button in the Equalizer block The window in Figure 3 11 will appear This is the 20 Band Graphic Equalizer Control Window The twenty vertical scroll bars or sliders are used to set the equalizer attenuation for each of the 20 frequency bands Use the mouse to set all sliders to match the settings shown in Figure 3 11 CGAY Page 20 35 Click on the Store button to bring up the Store 20 Band Graphic Equalizer window as in Figure 3 12 10 14 18 e e X e e e e Gain 15 10 6 6 4 2 2 6 6 6 6 6 6 4 4 6 T EA dB E a a a Ee Ee a E a a a a Fe H Make All OdB All Down 1dB Store Recall S Equalizer In L DE
31. level changes at a fraction of the rate of the increase of the input signal level The dynamic range of the output signal is reduced with respect to the input signal As an example a 2 1 compressor would produce an output level increase of 10 dB when the input signal decreases 20 dB Compression allows signals of wide dynamic ranges to be squeezed into more limited dynamic ranges of CAY Page 96 recording media and transmission channels Compression also eases listening especially for noisy audio Compressors are generally preferred over AGC s since input signal level differences are more modestly preserved Expansion Region In the expansion region the output signal has a wider dynamic range than the input signal Expansion is the opposite of compression As an example with an expansion ratio of 1 3 the output signal will increase 30 dB when the input signal decreases only 10 dB Expansion may be used to restore a signal s dynamic range following compression for example if a 2 1 compression has taken place a 1 2 expansion would restore the signal to its original dynamic range Expansion is also used to attenuate objectionable low level background sounds that are below voices Expansion Ratio 1 2 5 Compression Ratio LCE 21 Limiting Threshold f 30 dB Compression Threshold 70 dB Attack Time i ms Release Time d 50 ms Set for Nagra Expansion Current Gain 90 dB OdB 10dB 20dB 30dB 40dB 50dB
32. no loud sounds exceed the specified Threshold the Limiter will not affect the input signals In Stereo configurations the four inputs may be linked allowing an overload on any input channel to reduce the gain equally on all inputs which minimizes the impact on signal processing Clicking on the Limiter Button will cause its caption to toggle between Limiter In and Limiter Out as shown in Figure 4 5 indicating whether the Limiter is in or out of the process Figure 4 5 Limiter Button For fast access to the Limiter pressing lt Alt L gt may also be used to toggle the Limiter in or out of the process NOTE The Limiter Button is never overridden by the Processor In Out button The Limiter Setup button is used to adjust the control settings for the Limiter When this button is pressed the window shown in Figure 4 6 appears This window allows the user to adjust the Release Time Threshold and Link settings of the Limiter Release Time specifies how quickly input signal levels will return to normal after an overload condition goes away the shorter the Release Time the more quickly the levels will return to normal The Release Time options are 0 125 seconds fastest 0 250 seconds 0 500 seconds and 1 0 seconds slowest The 0 250 seconds setting is recommended for voice applications Release Time settings longer than 0 250 seconds may result in excessively long periods of reduced signal level after an overload occurs CAY Pa
33. proper communication has been established When you are ready to disconnect from the remote MCAP Click on File then Exit to exit the MCAP Master Control program This will cause your modem to hang up the telephone and break the connection CGAY Page 125 7 DEDICATED 920 LINE SPECTRUM ANALYZER OPERATION The SPECDISP EXE program provides a dedicated 920 line spectrum analyzer display using the ANALYZER PC RS232 jack on the rear panel of the MCAP The screen controls are the same as for the 920 line spectrum analyzer included with the MCAP Master Control software see Section 4 7 except that signal selection and averager controls are disabled Essentially this special utility program is slaved to the MCAP Master Control software it can only display the spectra as they are configured by the Master Control software To run the Dedicated Spectrum Analyzer first connect any available COM port on the computer that will run SPECDISP to the ANALYZER PC jack on the MCAP rear panel Then click on the Dedicated Spectrum Analyzer icon in the MCAP Software program group The program should automatically locate the MCAP ANALYZER PC port and begin displaying spectra CAY Page 126 8 PASSTHRU REMOTE MCAP OPERATION PASSTHRU is a Windows program that runs at a Remote Location and allows an operator at a Base Location to dial into the Remote Location and digitally link up to the distant MCAP Once the two locations are linked the
34. pulldown menu appears click on Open Setup File This will cause the following window Figure 4 65 to appear Setup Files Drives HUMBUZZ DAC amp c Directories ICs J PROGRA 1 DIGITA 1 Description AC HUM REMOVAL Date 0734 Thu 23 Feb 1995 Figure 4 65 Recall Setup File Window 2 Normally it will not be necessary to change the Drive or the Directories settings if however you need to recall a setup file from a different drive such as a floppy drive or directory scroll through the lists of available drives and directories and select the desired drive or directory by double clicking it If you select a drive that is not ready or a directory which has no setup files in it an error message will be generated 3 Each stored setup has a time stamp and a user entered text Description to uniquely identify it These are easily browsed prior to recalling a setup thus preventing time from being wasted if the wrong setup file is selected To browse a setup time stamp and Description scroll to and click on the desired file listed in the Setup Files list box G Page 113 4 Once the desired setup file name has been found either double click it or click on OK to recall it A message will alert the user that 60 seconds may be required to completely recall the setup An hourglass mouse cursor will now appear indicating that the MCAP is busy configuring itself with the recalled settings from disk 4 9 3
35. range somewhere below 300 Hz so that the voice signal will not be disturbed While listening to the filter output audio the Lower Cutoff Frequency initially set to 0 Hz can be incrementally increased until the quality of the voice just begins to be affected achieving maximum elimination of low frequency noise The Upper Cutoff Frequency is usually set above the voice frequency range somewhere above 3000 Hz so that the voice signal will not be disturbed While listening to the filter output audio the Upper Cutoff Frequency initially set to its maximum frequency can be incrementally lowered until the quality of the voice just begins to be affected achieving maximum elimination of high frequency noise The amount of volume reduction outside the passband region can further be controlled by adjusting the Stopband Attenuation setting maximum volume reduction is 60d0B The slope at which the volume is reduced from normal at each Cutoff Frequency to the minimum volume specified by Stopband Attenuation can also be controlled by adjusting the Transition Slope setting C4 EJ m Lower Cutoff Frequency r Upper Cutoff Frequency 2065 Hz 3545 Hz 4 d H gt Filter In Transition Slope Stopband Attenuation Lower 655 dB Octave Upper 2247 dB Octave ee H EEI Ig Figure 4 20 Bandpass Filter Control Window Description of controls is as follows Lower Cutoff Specifies frequenc
36. req 100 300 500 700 900 1 1K 1 3K 1 5K 1 7K 1 9K 2 2K 2 7K 3 2K 3 8K 4 4K 5 0K 5 6K 6 2K 6 8K 7 4K Lo Figure 3 11 Tutorial 20 Band Graphic Equalizer Control Window bp LS Click on desired memory or press cancel to exit 8kHz BW Memories Figure 3 12 Tutorial Store 20 Band Graphic Equalizer Window 36 Click on the 1 button to store your slider settings in Memory 1 We will recall these settings later Once you have clicked this button the system will automatically return to the 20 Band Graphic Equalizer control window 37 While listening to the OUTPUT audio with the headphones adjust the sliders and listen to how each affects the sound Remember you can drag the box click in the bar or click on the end arrows Also note that the gain value is displayed above each bar Observe the effect on the signal as the Equalizer button is toggled Each of the six system bandwidths has its own set of 10 memories CA Page 21 38 39 40 41 42 43 between Equalizer In and Equalizer Out Also note that whenever a slider is adjusted the Equalizer button will automatically be switched from Equalizer In if it was in Equalizer Out Click on the All Down 1dB button a few times and see how all the sliders move down together 1dB at a time This enables you to increase the gain of a slider previously at 0 dB Click on the Normalize button and see how all the sliders will instantly move up together so that the
37. taps but it can be set to as high as 8192 taps depending on System Bandwidth Configuration and Number DSP Stages settings Small filters are most effective with simple noises such as tones and music Larger filters should be used with complex noises such as severe reverberations and raspy power hums A nominal filter size of 512 to 1024 taps is a good overall general recommendation To access larger adaptive filter sizes click on the Adjust Maximum Size button The dialog box shown in Figure 4 14 should appear By default the current maximum adaptive filter size is selected clicking on OK or Cancel at this point will exit the window without resetting the filter However selecting any of the other options increasing or decreasing the maximum size will cause all adaptive filters to be cleared and reset the currently selected filter to the new maximum size when the OK button is clicked Click Cancel at any time to exit the Adjust Maximum Size window without affecting any filters Please Note Any time the maximum size of any adaptive filter is increased the Number DSP Stages options may be reduced and subsequent filter stages may be dropped due to the MCAP s physical CGAY Page 49 Adapt Rate Prediction Span Auto Fixed Mode Processor Output Filter Button Adapt Freeze limitation of 8192 total filter taps for all filters When this increase occurs the Oversized Filters caption will appear in the Number DSP Stages
38. the Bandstop filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the Bandstop filter and its controls follows in Figure 4 23 Attenuation dB Lower Transition Slope E lt Upper Transition Slope dB Octave dB Octave Stopband A ti Lower Upper T ON lL ower Passband Transition Stopband ens a8 Upper Passband Band 1 Bond Lower Upper Cutoff Cutoff Frequency Hz Frequency Frequency Figure 4 23 Bandstop Filter Graphical Description 4 4 7 Comb Filter Application The Comb filter is used to remove or notch out harmonically related noises noises which have exactly equally spaced frequency components such as power line hum constant speed motor generator noises etc from the input audio The filter response consists of a series of equally spaced notches which resemble a hair comb hence the name Comb filter Adjust the Comb Frequency to the desired spacing between notches also known as fundamental frequency Set the Notch Limit to the frequency beyond which you do not want any more notches Set the Notch Depth to the amount in dB by which noise frequency components are to be reduced Normall
39. you have misidentified the COM port Repeat steps through 3 until the Status Icon shows an animated pictures of a data port with an arrow moving through it When it does wait a few moments for the program to reset the external processor If the Input Level bargraphs eventually respond to the input signal then proper communication has been achieved CAS Page 120 4 Click on File then Exit to exit the MCAP Master Control program This will save the new COM port setting 6 2 Configuring MCAP for Different Baud Rates This section is intended for advanced users only The MCAP system is capable of operating at RS232 symbol rates of 9600 14400 19200 and 38400 baud Each MCAP is factory configured to operate at 38400 baud which works well for most PCs However some applications such as modem or network links may require the use of a different baud rate Change the MCAP baud rate as follows 1 First reset the internal DIP switches of the external processor for the new baud rate as follows a Power off the MCAP external processor and disconnect all cables especially the EXTERNAL POWER and RS222 cables b Carefully remove the external processor top cover by first removing the screws located behind the front panel rack mount ears with a phillips screwdriver then sliding off the top cover toward the rear of the unit C Locate the orange 5 position DIP switch near the front of the internal printed circuit board Set DIP switc
40. 4 Always E 0000 111 milliseconds EE E 10dB 0 S a C If Input gt Threshold a 3 Wi Ce Auto C Fixed 6 If Input lt Threshold 12 Ft Size 1024 taps max Processor Output Clear R 18 C If Residue gt Threshold Ss 32 taps G Residue il C If Residue lt Threshold e 0001 778 milliseconds C Predict Ee z 36 V i i Adjust Maximum Size G Page 48 Figure 4 15 1CH Adaptive Filter Control Window Description of controls Figure 4 15 is as follows Conditional Adaptation Filter Size For advanced users only Novice users should keep Filter will adapt set to Always The Threshold setting is meaningless in this case Conditional Adaptation allows the adaptive filter to automatically Adapt Freeze based upon signal input or output This can be very useful in situations where there are pauses or breaks in the speech being processed For example if you only desire the filter to adapt when no one is talking you will first need to observe the Input bargraph levels to determine the dB level below which no talking occurs Then click on If Input lt Threshold and set the Threshold to the observed dB level Click on the Clear button if you desire the filter to completely readapt based upon the new Conditional Adaptation settings Used to set the number of FIR filter taps filter order in the adaptive filter Filter size is indicated both in taps and in milliseconds Minimum Filter Size is 4
41. 6 5 8 0 11 and 16 kHz The MCAP is designed to replace an entire rack of audio processing equipment With monophonic signals as many as thirteen sequential stages of processing twelve of which are digital can be performed simultaneously With stereo signals nine sequential stages of stereo processing eight of which are digital for each channel are also available The digital stages can implement a broad selection of filter types An easy to use Microsoft Windows based Master Control program allows intuitive control of the entire process including bandwidth selection mono stereo configuration and number of digital processing stages Individual process controls and filter modes for each digital stage are easily specified Input and output level bargraphs are displayed and the signal frequency spectrum at any point in the process can be displayed utilizing the MCAP s built in 920 line spectrum analyzer CA Page viii 1 1 1 SYSTEM BASICS System Configuration The basic configuration of the MCAP system is illustrated in Figure 1 1 Computer Source Tape Player A 7 COOC MCAP EE 520 OO O O fose Enhanced Tape Recorder E Z La oo0o00 Headphones Figure 1 1 MCAP System Configuration The MCAP Master C
42. 6 x 2 14 is therefore equal to 0 016 CGAY Page 47 Output Filter Button Adapt Freeze Button Clear Button Selects Residue or Filter output The Residue output is the normal output selection which is the signal left over after the modified Reference signal has been subtracted from the Input signal The Filter output is the modified Reference signal that is subtracted from the Input signal to produce the Residue output Used to switch the Ref Canceller filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process Used to freeze this adaptive filter independently Used to reset the coefficients of the 2CH Adaptive filter to zero without affecting any other adaptive filters in the process NOTE The same Filter Clear and Adapt Freeze buttons are also available in the Filter block for each filter on the Master Control Panel 4 4 2 _1CH Adaptive Filter Application The 1CH Adaptive filter is used to automatically cancel predictable and convolutional noises from the input audio Predictable noises include tones hum buzz engine motor noise and to some degree music Convolutional noises include echoes reverberations and room acoustics EJ x r Conditional Adaptation Prediction Span Adapt Rate OL Filter will adapt 2 samples Mu 256 x2 1
43. AIN OUTPUTS line output signals The headphones will be restored to their original state when the Path Delay Window is exited 4 2 2 Input and Output Highpass Filters HPFs Application The Inout HPFs are used to remove rumble or other low frequency noises which occur below 100 Hz to 500 Hz adjustable from the input signals before they enter the digital processors Since very little speech information is lost in bandlimiting below these frequencies this filter is recommended for voice enhancement However for wide bandwidth and Hi fi signals the low frequency cutoff may result in some loss of desired signal components The Output HPFs function the same as the Input HPFs except that they remove low frequency noise after the input signal has passed through the digital processors Signal processing may restore some of the low frequency energy Clicking on the Input HPF Button will cause its caption to toggle between Input HPF In and Input HPF Out as shown in Figure 4 3 indicating whether the Input HPFs are in or out of the process Similarly clicking on the Output HPF Button will cause its caption to toggle between Output HPF In and Output HPF Out as shown in Figure 4 3 indicating whether the Output HPFs are in or out of the process CGAY Page 36 Figure 4 3 Input and Output HPF Buttons For fast access to the Input and Output HPFs pressing lt Alt I gt or lt Alt O gt may also be used to toggle the Input or Output HP
44. AP for Different COM Porte 120 6 2 Configuring MCAP for Different Baud Rates 0 eecceeeeeeeeeeeeeeeeeeeeeeneeeeeeeees 121 6 3 CUSTOMIZING Screen Colors sesoun iaieiiea 123 6 4 Operating a Remote MCAP via Modem 123 7 DEDICATED 920 LINE SPECTRUM ANALYZER OPERATION 126 8 PASSTHRU REMOTE MCAP OPERATION 127 8 1 General System Configuration And Operation ceeeeeeeeeeeeeeeeeeeneeeeeeeees 127 8 2 Program Features anmlKCIOIEERSeeeekuegeeheNEAeeSEEEEEEEEEA EE EENehEE 128 8 2 1 PASS THRU Progen reesen REES 128 8 3 PASSTHRU Program Main Gcreen EEN 129 8 3 1 PASSTHRU Configure Drop Down Men 130 8 4 Program Operalom niin sesp eesti n aaa ths te eee cee tate ie les cates 131 8 4 1 Base Location One Time Initialization Only 0 0 0 eecceeeeeeeeeeeteeeeeeeeeees 132 8 4 2 Remote Location One Time Initialization Only 0 eeeeeeeeeeeeteeeeeeeeees 132 8 4 3 Remote Location Normal Operation Each Gessaion eerren 133 8 4 4 Base Location Normal Operation Each Session ssssseessseeeeer enneren 134 8 4 5 In Case Of Trouble EEN 134 9 MCAP SPECIFICATIONS EE 136 CAY Page iii LIST OF FIGURES Figure 1 1 MCAP System Configuration Abbe 1 Figure 1 2 MCAP Functional Block DidQrain icciccccicpteetes saceciceptestisabigstacchlenteisplestigubleetes 3 Figure 1 3 MCAP Front EE 4 Figure 1 4 MCAP Rear Panel iecisccses ces riirii aa daada iaa aa aa Laaa ELE eaaa 5 Figure 2 1 MCAP Master Control ICON
45. B at any point along filter curve Hold the left Mouse button down while editing the curve or drawing a new curve These readouts below the grid indicate precise frequencies and attenuations Releasing the button draws the segment This button allows the user to store a filter curve to any of 60 disk memories 10 for each of the six System Bandwidth settings which will not be lost when the computer is turned off Clicking this button brings up the following window Figure 4 45 m x Click on desired memory or press cancel to exit 3 2kHz BW Memories A stored memory is available to all filter stages and is configuration dac file independent Figure 4 45 Hi Res Filter Store Window Clicking one of the 10 jukebox style buttons will cause the current filter curve to be stored in that disk memory for the current System Bandwidth Clicking the Cancel button exits the Store window without storing the filter curve in any of the memories This button allows the user to recall a previously stored filter curve from one of 11 disk memories for the currently selected System Bandwidth Clicking this button brings up the window shown in Figure 4 46 CGAY Page 86 Click on desired memory or press cancel to exit 8kHz BW Memories Previous Figure 4 46 Hi Res Graphic Filter Recall Window Clicking one of the 10 jukebox style buttons will cause the filter curve to be configured as previously stored Clicking the el
46. Base Location has full control of the MCAP 8 1 General System Configuration And Operation Figure 8 1illustrates the connection between the various components of the remote controlled MCAP system At the Remote Location the PC is running the PASSTHRU program This PC is connected to both the MCAP and the MODEM via two separate serial communication ports Since this PC will also be connected to a mouse a total of three serial ports is necessary The MODEM is also connected to the local telephone company line At the Base Location the PC is running the normal MCAP Master Control Software This PC is connected to the MODEM via serial port As above since this PC will require a mouse a total of two serial ports may be necessary unless a PS 2 mouse is used The MODEM is also connected to the local telephone company line Telephone Exchange Remote Location Base Location Figure 8 1 System Configuration When the Base Location operator starts the MCAP control program the base PC dials the Remote Location The remote MODEM detects the ringing phone the remote operator must already have started the PASSTHRU program answers it and tries to establish a digital link with the caller PASSTHRU performs caller authentication by CAY Page 127 transferring handshaking codes to the caller and requesting a maximum 25 character user entered password Once the caller is authenticated the remote PC becomes a digital gateway between the base
47. CH Adaptive Filter i 2 0n2i0naeaadaie areata elias 48 e LOW DASS EE 52 4 4 4 Highpass Filter EE 53 4 4 5 Bandpass E 55 4 4 6 le tere EE 58 AAS COME FING A A A AA 60 4 4 8 InmverseCombbiter 63 4 4 9 Cette BEE 65 4 4 10 Multiple Notch E 67 A ALTAR OIOU TEE 69 4 4 12 Multiple Slot EE 71 4 4 13 Spectral Inverse Eiter 74 4 4 14A Res Graphie EE geseet geegent Gees Geh 85 4 4 15 20 Band Graphic TUTE 92 Select eave a D eee gee Ee eet eb ee 93 4 4 17 Limiter Compressor Expander unn 95 4 5 DSP Equalizer Control WINdOWS sseseeessessnennnreeeseesnnrnrrrnnseerrrnnnnnnnneserrnrn nnn 99 4 5 1 20 Band Graphic GREEN 99 4 5 2 Spectral Graphic e UE ME 101 4 5 3 Dual Parametric Eoualtzer ee 102 4 5 4 Limiter Compressor Expander en 102 4 6 D SbRESplew Geleehtet ege Ze nde geed e E 103 4 6 1 Spectrum Analyzer and Coefficient Display Buttons sesssssseeeee eenen 103 4 6 2 Display Select Wumdow 103 4 7 Spectrum Analyzer WihdOW EE 104 4 8 Coefficient Display Wumdow 108 4 9 Master Control Pulldown Menus 111 4 9 1 Storing Setups to Disk UE 111 4 9 2 Recalling Setups from Disk FPles 112 4 9 3 VIEWING DSP DISplay EE 114 4 9 4 Storing Setups to External Processor Stand Alone Memories 114 4 9 5 Generating Setup Reports ee 116 4 9 6 Getting Online Help EE 116 5 OPERATING MCAP GTAND ALONE 118 6 MCAP CUSTOMIZATION OPTIONS vgticteccidinictattccictattieinintiiacctntinteiaddaninattioteeatict 120 6 1 Configuring MC
48. Control Window When Equalize Voice Selected Description of controls indicators is as follows Filter Display Analyzer Block Used to display the original audio spectrum Yellow Trace Filter Input and the spectral inverse filter curve Blue Trace Filter Shape For each trace 460 spectral lines and 70dB of dynamic range are displayed A green grid is superimposed to aid the user in determining frequency and amplitude Used to control the spectrum analyzer which measures the original audio power spectrum this spectrum is displayed and continuously updated in the Filter Display area as a yellow trace Analyzer controls include Clear button which is used to zero the averager memory and cause the averaged spectrum to be recalculated anew Run Freeze button which allows the user to start Run indication or stop Freeze indication update of the averaged spectrum Num Averages setting which allows the user to specify the degree of smoothing of the original audio power spectrum For minimum Filter Operation Block Range Gain Block smoothing set to 1 for maximum smoothing set to 128 A long term power spectrum 64 to 128 averages is best for setting up the filter Gain control which allows the user to apply a digital gain of up to 40dB to the analyzer input allowing low level spectrum components to be revealed however if excessive gain is applied the analyzer input will overload causing the Gain label to cha
49. Fs respectively in or out of the process Adjustment of the Input HPF cutoff frequency is accomplished by clicking on the IHPF Setup button When this button is pressed the window shown in Figure 4 4 appears Cutoff Frequency 200 Hz Figure 4 4 Input HPF Setup Window Specify the cutoff frequency in 10 Hz increments using the slider control Minimum cutoff frequency is 100 Hz while the maximum cutoff frequency is 500 Hz Similarly the Output HPF cutoff frequency can be adjusted by clicking on the Output Setup button to bring up the Output HPF Setup Window identical to the Input HPF Setup Window shown in Figure 4 4 NOTE Both the Input HPF and Output HPF buttons are overridden by the Processor button When the Processor button is set to Processor Out both the Input HPF and the Output HPF will be bypassed regardless of their buttons status Fast access keys use the Alternate key and the underlined letter simultaneously The letter is not case sensitive i e lt Alt i gt and lt Alt I gt are interpreted the same way CGAY Page 37 4 2 3 Digitally Controlled Limiter Application The four channel input Limiter automatically protects the input circuits from overload distortion by reducing input signal levels whenever loud sounds such as door slams exceed a specified Threshold When the overload goes away the Limiter returns the input signal levels to their original settings over the specified Release Time interval If
50. MCAP MULTI CHANNEL AUDIO PROCESSOR Creating New Directions in Digital Audio Electronics MCAP MULTI CHANNEL AUDIO PROCESSOR User s Manual Version 4 2 Revised May 10 2000 Document Number 960598A Digital Audio Company A DRI Company 5121 Holly Ridge Drive Raleigh NC 27612 Phone 877 5DACAUD 532 2283 Fax 877 5DACFAX 532 2329 www dacaudio com Copyright 2000 by Digital Audio Company All rights reserved TABLE OF CONTENTS PORE WORD sees ere eae eee ee es vii SYSTEM Le 1 1 1 System Config ralo E 1 1 2 External Processor e TE 2 1 3 External Processor Front Panel EE 3 1 4 External Processor Rear Panel ENEE 5 2 INSTALLATION INSTRUCTIONS ce4n veun te vei ae eine 6 E Dee RE 6 RE e ee E 6 2 3 Firmware Update Procedure scteccccehti crest deceit fer 8 6 GE EMING AP Eege eege 10 eh GE 10 3 22 MGAP T tonal caters Car aera i netic ei ett A AREA eer iA tet A iat teeta 13 3 3 Training CD Recording DEE 29 4 MCAP SOFTWARE REFERENCE MANUALE 31 4 1 Master Control Panel EE 31 4 2 Input and Output e 35 4 2 1 Input Path Delay IESSE 35 4 2 2 Input and Output Highpass Filters Hei 36 4 2 3 Digitally Controlled Limiter een 38 4 2 4 Digitally Controlled AG 40 4 2 5 On Screen Headphone Control 41 4 3 DSP Processor Selection un 42 4 3 1 Filter Selection VWI EEN 42 4 3 2 Equalizer Selection Wmdow 44 4 4 DSP Filter Control WINdOWS e ee EE 44 4 4 1 Ref Canceller formerly 2CH Adaptive Eiter 45 4 4 2 1
51. OK button in the Lowpass window to return to the Master Control Panel To return to the Spectrum Analyzer display click on View and select the Spectrum Analyzer menu option as shown in Figure 3 15 Note that this menu option allows the user to access either the Coefficient Display or the Spectrum Analyzer display or to turn all Displays Off Click on Spectrum Analyzer to return to the Spectrum Analyzer window This two step sequence is the same as clicking on the Spectrum Analyzer Button in the Master Control Panel step 43 Coefficient Display v Spectrum Analyzer Displays Off Figure 3 15 Tutorial Display Select Menu Now turn off the spectrum analyzer by clicking on the Close button in the Spectrum Analyzer window The system will now return to the Master Control Panel Access the Save Setup File feature by clicking on File in the menu bar The pulldown menu in Figure 3 16 will appear Click on Save Setup File to bring up the Save Setup File window as shown in Figure 3 17 For now do not change the Drives or Directories settings just keep in mind that you could change these settings to allow setup files to be stored to any directory of any drive The Spectrum Analyzer functions may be adjusted by moving the mouse cursor to that window The spectrum Analyzer window may not by closed at this time however CGAY Page 25 New Filter Configuration Open Setup File View File Description Exit Figure 3 16 Tutori
52. Selecting Even will generate slots at 120 Hz 240 Hz 360 Hz etc Filter Button Used to switch the Inverse Comb filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel 4 4 9 Notch Filter Application The Notch filter is used to remove or notch out a narrow band noise such as a tone or a whistle from the input audio with minimal effect to the remaining audio The Notch filter works best with stable noise sources which have constant frequency if the frequency of the noise source varies then the 1CH Adaptive filter is recommended To properly utilize the Notch filter you will first need to identify the frequency of the noise this is best done using the Spectrum Analyzer window See Section 4 7 for complete instructions on operating the Spectrum Analyzer window Initially set the Notch Depth to 60 dB and the Notch Width to the narrowest possible value Next set the Notch Frequency to the noise frequency Fine adjustment of the Notch Frequency may be necessary to place the notch precisely on top of the noise signal and achieve maximum reduction of the noise This is best done by adjusting the Notch Frequency up or down 1 Hz at a time while listening to the Notch filter output on the head
53. Transition Slope is set to minimum Note that the indicated value changes depending upon Cutoff Frequency System Bandwidth Configuration and Number DSP Stages settings Used to switch the Highpass filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the highpass filter and its controls is as follows in Figure 4 19 Attenuation dB Stopband Transition Slope dB Octave gt Attenuation dB Stopband EE Passband an Cutoff Frequency Hz Frequency q y Figure 4 19 Highpass Filter Graphical Description 4 4 5 Bandpass Filter Application The Bandpass filter is used to decrease the energy level lower the volume of all signal frequencies below a specified Lower Cutoff Frequency and above a specified Upper Cutoff Frequency thus combining the functions of a seriesed Lowpass and Highpass filter into a single filter The signal region between the Lower Cutoff Frequency and the Upper Cutoff Frequency is called the passband region The Bandpass filter is useful for simultaneously reducing both low frequency rumble and high frequency hiss CGAY Page 55 The Lower Cutoff Frequency is usually set below the voice frequency
54. ad the text in the Current Status box This information is designed to help the remote operator correct any problems Problem PASSTHRU is waiting for the remote user to call but the MODEM never seems to detect a ringing phone Suggestion CAY Page 134 Make sure the phone line is plugged into the correct jack on the MODEM Make sure the phone line is active by plugging a regular phone into the phone line and verifying the presence of a dial tone Make sure the settings in the Advanced Session Setup are correct CGAY Page 135 Analog Input Output Line Inputs 4 Line Outputs 2 Headphone Outputs Input Level Indicators Bandwidth Analog Conversion Signal Processing Dynamic Range Digital Input and Output Interface MCAP SPECIFICATIONS Four rear panel BNCs Balanced differential input Zin 25kQ level adjustable 8 to 15 dBm Two rear panel BNCs Zou 100Q Level 8 dBm Dual front panel stereo jacks with volume control Source switches for monitoring MCAP s Main inputs Reference inputs or Outputs Left Stereo Right selection Four tricolor LEDs Red 6 dB orange 12 dB green 18 dB 3 2 5 4 6 5 8 0 11 0 and 16 0 kHz selectable 35 Hz AC input coupling Two 24 bit sigma delta stereo A D converters on analog inputs 24 bit delta sigma stereo D A converter for line outputs 24 bit delta sigma stereo D A converter for headphone monitoring 7 2 12 14 4 18 24 and 36 kHz
55. al File Pulldown Menu m x Description Store in File Name dac C PROGRA 1 DIGITA 1 MCAPV40 Directories Drives a CA Sc M lt JPROGRA 1 y DIGITA 1 Cancel IT Protect from future overwrite Figure 3 17 Tutorial Save Setup File Window 58 Click your mouse cursor on the Description text box which should currently contain only the dac extension Using your keyboard delete all characters in the text box then type in My First Setup See Figure 3 18 CA Page 26 59 60 61 62 63 64 By x Description My First Setup Store in File Name mysetup dac C PROGRA 1 DIGITA 1 MCAPY 40 Directories Drives A CA Cc e a PROGRA 1 y DIGITA 1 Cancel Protect from future overwrite Figure 3 18 Tutorial Store in File Name Text Box Now click your mouse cursor on the Store in File Name text box Use the left arrow key to move the cursor to just before the dac extension then type mysetup These entries should appear as in Figure 3 18 Click on OK to store your first setup file and return to the Master Control Panel Click on File to access the File Pulldown Menu as in step 56 Click on Open Setup File to bring up the Open Setup File window similar to Figure 3 3 but with mysetup dac added to the Setup Files list For now do not change the Drives or Directories settings just keep in mind that you could change these settings t
56. al Inverse Hi Res Graphic 20 Band Graphic Tri Parametric Inverse Comb Compressor Expander Notch huttiple Motch Filter Out Figure 3 7 Tutorial Filter Selection Window and Combo Box 21 Select Lowpass for the Fitler 2 block using the same technique as in step 20 22 Click on the Control button in the Filter 1 block The window in Figure 3 8 will appear SS LS Conditional Adaptation Prediction Span Adapt Rate oL Filter will adapt Mu 256 x 2 14 Threshold s Se Always 10dB a 0000 111 milliseconds aj D C IfInput gt Threshold All C It lnputTbhresbokd ES C If Residue gt Threshold RW If Residue lt Threshold A 32 taps 0001 778 milliseconds EI L Auto C Fixed Filt Size 1024 taps max Processor Output Clear Residue Adapt C Predict gt Filter Out El Figure 3 8 Tutorial 1CH Adaptive Filter Control Window This is the 1CH Adaptive Filter Control Window It is used to select Filter Size Adapt Rate Prediction Span and Adapt Mode It also permits configuration of the 23 24 25 26 27 28 filter for Conditional Adaptation see Section 4 4 2 for further information on how to setup this filter Use the mouse to set all controls to match the settings shown in Figure 3 8 Do not click on the OK button at this time Listen to the filter OUTPUT through your headphones Note the effect on the signal as the Filter button is toggled between Filter In and Filter
57. analog tape recorder s wow flutter Table 3 1 MCAP Training CD Summary 4 MCAP SOFTWARE REFERENCE MANUAL This portion of the user s manual is designed as a reference guide to which the user may refer for more detailed information on specific windows in the MCAP Master Control program It is assumed in this section that the user has a good working knowledge of Microsoft Windows has properly installed the MCAP hardware and software using the installation instructions in Section 2 2 and has completed the MCAP Tutorial Section in 3 2 4 1 Master Control Panel Configuration Bax Input Levels Box Menu Bar System Bandwidth Box Filter Boxfes Output Box System andwidth Bett Ref2 Ref3 C 3 2kHz 8 kHz Output Level Out Select Control oL C 5 4kHz C 11 kHz Fiker Out A C 6 5kHz C 16 kHz Adapt Clear 3 Filter 2 A Configuration oOwpass D Mono Select Control c z 15 Stereo Linked Filter Out ES C Stereo Indep 24 Number DSP Stagas Box 30 Number DSP Stages 39 o o a e 8 EI ees SEN ai ai ai ai Clear All AGC Out Adapt Enabled AGC Setup x E Z Pr cessor In Equalizer Headphones Claer Al Button Processor Button Equalizer Box es Coefficient Display Button Spectrum Analyzer Button Figure 4 1 Master Control Panel Features When the MCAP Master Control program is run from Microsoft Windows the Master Control Panel appears The Master Con
58. apes the audio to a normal spectral shape might be desirable The Hi Res Graphic Filter is essentially a 460 band graphic equalizer however instead of having 460 separate slider controls it allows the user to precisely draw the desired filter shape on the computer screen using the mouse with as much or as little detail as desired Once the filter shape has been drawn a linear phase digital filter is constructed in the PC and transferred to the external MCAP unit The Edit feature allows the user to make readjustments to the filter shape while the Normalize button allows the user to shift the entire filter curve up until the highest point is at OO A Store and Recall capability is also provided to allow the user to store commonly used filter shapes to disk memories so that they can be recalled later Edit Normalize Store Recall Filter In OK fk Figure 4 44 Hi Res Graphic Filter Window Description of controls indicators is as follows Filter Display Graphically displays the current shape of the filter Also used in conjunction with the mouse to draw a new filter shape or to edit an existing one see New Edit and Normalize button descriptions A CGAY Page 85 Freq and Atten Readouts Store Button Recall Button grid is provided to assist the user in visually judging frequency and attenuation at any point in the display Used to precisely readout the frequency in Hertz and attenuation in d
59. average at any time by clicking on the Clear button Display Section Allows the user to display the Yellow and Blue spectral traces simultaneously or separately Selecting Yellow displays the Yellow Trace only selecting Blue displays the Blue Trace only and selecting Both displays both the Yellow Trace and the Blue Trace Trace update rate will be slightly faster when Yellow or Blue is selected Yellow Signal Defines what is displayed by the yellow colored spectrum trace The Select Yellow Signal Select box highlights the currently selected signal and allows Blue Signal Select the user to scroll through the available signals and select a different one with a mouse click The Gain scroll bar allows the user to apply digital gain to the Yellow Trace input signal prior to FFT analysis allowing signals which fall below the 70dB dynamic range of the analyzer to be viewed Gain may be adjusted from OdB no gain to 40dB This Gain setting does not affect the audio only the Spectrum display If the Gain setting is too large the Yellow Trace input may be overloaded causing a distorted spectrum display When an overload does occur the Gain label will change to OVL and the yellow magnitude readout at the bottom of the display will change from yellow to red Overloads affect only the display and have no effect on the processed signal Defines what is displayed by the blue colored spectrum trace The Blue Signal Select box highlights the c
60. but will allow more precise removal of high frequency noises Note that the indicated value changes depending upon Cutoff Frequency System Bandwidth Configuration and Number DSP Stages settings Filter Button Used to switch the Lowpass filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the lowpass filter and its controls is given in Figure 4 17 Attenuation dB Stopband RE Graham Transition Stopband off Frequency Hz Figure 4 17 Lowpass Filter Graphical Description Frequency Hz 4 4 4 Highpass Filter Application G Page 53 The Highpass filter is used to decrease the energy level lower the volume of all signal frequencies below a specified Cutoff Frequency thus reducing low frequency noises such as tape or acoustic room rumble from the input audio The Highpass filter is sometimes called a rumble filter The Cutoff Frequency is usually set below the voice frequency range somewhere below 300 Hz so that the voice signal will not be disturbed While listening to the filter output audio the Cutoff Frequency initially set to 0 Hz can be incrementally increased until the quality of the voice just beg
61. call Button This button allows the user to recall a previously stored spectral inverse filter curve from one of 11 disk memories for the currently selected System Bandwidth Clicking this button brings up the window in Figure 4 39 Clicking one of the 10 jukebox style buttons will cause the filter curve to be configured as previously stored Clicking the eleventh button labelled Previous will cause the curve to be restored to the shape it CA Page 80 had prior to the last memory recall at the current System Bandwidth setting Successive clicks of Recall then Previous perform A B comparison of two filter curves Examples of Spectral Inverse Filters In the examples below SIF will equalize a voice spectrum using various EQ Ranges and Output Shapes When the Range is small only the peaks in the spectrum are flattened As the Range is increased lower energy segments are equalized The top trace in each of the figures below gives the filter curve and the bottom trace gives the original input spectrum In Figure 4 40 Figure 4 41 and Figure 4 42 the EQ Range is increased Each increase in Range is accompanied by an increase in compensating Gain Compare the filter curve top to the original input spectrum bottom As the EQ Range is increased more peaks are attenuated Figure 4 42 completely compensates all peaks and valleys Note also the 40 dB attenuation outside the two Limits Ei x m Analyzer Filter Operation EQ Rang
62. cancelled in real time if the original broadcast audio usually available from a second receiver is simultaneously connected to the RIGHT REF1 MAIN INPUT Optionally the LREF REF2 and RREF REF3 REF INPUTS are also available for canceling multiple interfering Sources 7 LS r Conditional Adaptation Reference Select Delay Channel Delay Filter will adapt Threshold S Rel C Ref3 Input 1 samples Always 10dB C Bet Fineness 0000 056 milliseconds If Input gt Threshold Z x4 S If Input lt Threshold Filt Size 1024 taps max Adapt Rate Output C If Residue gt Threshold 2 288 taps Mu 4 x2 14 Residue C If Residue lt cThreshold Se em mmm emm TIR Ir ee If Reference gt Threshold A go E C If Reference lt Threshold Ze Adjust Maximum Size Clear Adapt Filter In Figure 4 13 Ref Canceller Filter Control Window Description of controls Figure 4 13 is as follows Conditional Adaptation For advanced users only Novice users should keep Filter will adapt set to Always The Threshold setting has no effect in this case Conditional Adaptation allows the adaptive filter to automatically Adapt Freeze based upon signal input or output levels This can be very useful in situations where there are pauses or breaks in the speech being processed Hint Conditional adaptation is useful in maintaining adaptation once the filter has converged Motion in the room and air temperature c
63. d is complete the mouse cursor will return to normal and the calculated spectral inverse filter curve will be displayed as a blue trace in the Filter Display area Hint Before clicking the Build button it is recommended that the spectrum analyzer be set to Freeze to allow experimentation with the control settings for the same input spectrum Used to switch the Spectral Inverse filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process Whenever the Build button is clicked this button will always be set to Filter In NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel This button allows the user to store a calculated spectral inverse filter curve to any of 60 disk memories 10 for each of the six System Bandwidth settings which will not be lost when the computer is turned off Clicking this button brings up the window shown in Figure 4 38 CGAY Page 79 Mr LS Click on desired memory 8kHz BW Memories Figure 4 38 Spectral Inverse Filter Store Window Clicking one of the 10 jukebox style buttons will cause the current filter curve to be stored in that disk memory for the current System Bandwidth p x Click on desired memory 8kHz BW Memories Previous Figure 4 39 Spectral Inverse Filter Recall Window Re
64. de Num Averages Geisel Cleo Fun kg Gg a Figure 3 14 Tutorial Spectrum Analyzer Window Set the Gain controls for the Yellow trace to 40dB and the Blue trace to OdB While the demo audio is playing notice how the word Gain changes to OVL display overload for the Yellow trace and how the magnitude Mag indication for the Yellow trace changes color from yellow to red whenever strong peaks occur Reduce the Gain to prevent overload distortion from affecting the spectral display Return both Gain controls to OdB Click outside the Spectrum Analyzer window on the Master Control Panel window to bring up that window leaving the spectrum analyzer active Do not close the Spectrum Analyzer window Make sure that the two HPFs Limiter AGC Filters and Equalizer are all switched OUT Click on the Filter 2 Control button to bring up the Lowpass filter control window The GAIN affects the display only enabling weaker signals to be seen an OVL indication will not distort the processed audio 51 52 53 54 55 56 57 Notice how the Lowpass and Spectrum Analyzer windows are displayed on the same screen Click the Filter button in the Lowpass window until it indicates Filter In The Yellow trace now displays the signal going into the Lowpass filter while the Blue trace displays the signal coming out of the Lowpass filter Adjust any of the Lowpass filter controls noting the effect on the Blue trace Click on the
65. e 3 4 will appear CGAY Page 13 Eile Settings View Stand Alone ReportGenerator Help Input Levels System Bandwidth Filter 1 Output Levels Pri Refi Ref2 Ref3 C 3 2kHz 8 kHz ICH Adaptive D Dut oL oL oL Select Control oL C 54kHzC 11 kHz Filter Out 3 s z z C 6 5kHz 16 kHz Adapt Clear z 3 3 3 3 Filter 2 Configuration 3 3 3 owpass 3 12 12 12 CG Mono Select Control ae S Re Set C Stereo Linked 5 Re 18 18 18 Filter Out 18 24 24 24 C Stereo Indep 24 30 30 30 30 a eo Number DSP Stages 5 48 48 48 e ew 48 57 57 57 C3 CE 57 63 63 63 63 amp amp 9 el e E E oj ioj oj oj Clear All AGC Out Adapt Enabled AGC Setup fe fe E EJ Processor In Equalizer Headphones Limiter Out Path Delay 20 Band Graphic D Coefficient Display Selec CoA T Limiter Setup IHPF Out Setup Spectrum Analyzer Equalizer Out EN CLO e Ti Figure 3 4 Tutorial Master Control Panel This is the Master Control Panel from which all features can be accessed The Master Control Panel is organized logically from left to right with audio input controls at the far left digital processing controls in the middle and audio output controls at the far right 2 Use the mouse to set up the Input HPF In Out Limiter In Out Output HPF In Out AGC In Out System Bandwidth Configuration Number DSP Stages Adapt Enabled Disabled and Processor In Out buttons as they are sh
66. e COM port which is connected to your modem internal or external Next click on Remote Connect Settings then Baud Rate Select the baud rate at which your modem communicates with your PC this is not the same rate at which telephone communication of data occurs Click on Remote Connect Settings then Phone Number Password to bring up the following window Modem Phone Number EU 95554444 Modem Password W CAPPASSWORD OK Figure 6 4 Modem Phone Number Password Window G Page 124 Type in the telephone number of the remote site s modem as well as the password that the PASSTHRU EXE program expects When you are satisfied that these are typed correctly click on OK To attempt remote connection through this port first make sure that the PASSTHRU EXE program is operating on the remote site s computer which must be connected to both a modem and the MCAP Then click on Settings then Connect to Remote MCAP If any error messages appear there are many potential causes PASSTHRU not running and or not properly configured at remote site local modem not properly connected bad password wrong phone number etc Recheck all connections and settings then repeat steps 1 through 5 until Status Icon shows the connection is working When it does wait a few moments for the program to reset the remote external processor If the Input Level bargraphs eventually respond to the input signal then
67. e Gain f gt Run Sam Range 10 dB Build OdB Equalize Yoice q gt nun Averages C Attack Noise Gain K aT AEE ro e Store Lower Yoice Limit r Upper Voice Limit Output Shape 281 Hz 3164 Hz Flat C Voice Recall IT IR mm mmm 1e OK Figure 4 40 EQ Voice operation EQ Range set to 10db Output Shape set to Flat CAY Page 81 3 x Analyzer Filter Operation EQ Range Gain ceai Run Ka SI S Range 20 dB Build Equalize Voice 7 Hun yoro C Attack Noise cm 10 e SS al 2 Cem 1 7 SS SCH We Store Lower Voice Limit m Upper Voice Limit Output Shape 281 Hz 3164 Hz Flat Voice Recall Al II a gt Pink ox Figure 4 41 SIF with EQ Range set to 20dB The Output spectral Shape may be selected as Flat as illustrated Figure 4 40 Figure 4 41 and Figure 4 42 above It may also be set to Voice or Pink The Attack Noise mode does not attenuate Out of Limits signal but equalizes and attenuates in Limits signal frequencies Figure 4 43 illustrates Applications Suggestions The following suggestions may be beneficial in setting up and operating the Spectral Inverse filter Analyzer The FFT spectrum analyzer automatically produces the power spectrum of the signal entering the SIF For SIF to be effective a smoothed spectrum is necessary SIF adjusts for long term stable noises including resonances and steady noises Short term effects of voice and non stationary noises will decrease
68. e of each or you can set colors manually by selecting the item in the window example If you do set colors manually make sure that you click the Save As button to save your custom color scheme to a disk file Finally when you have all colors set the way that you like click on OK to reset the Windows environment colors to these values For complete details on using the Control Panel please refer to the Microsoft Windows User s Guide 6 4 Operating a Remote MCAP via Modem The MCAP Master Control software is factory configured to communicate directly with the locally connected external processor over RS232 communications port 2 COM2 However the PASSTHRU EXE program when properly configured at a remote location will allow the MCAP Master Control software to dial up and connect to an MCAP running at a remote location To utilize this feature follow this procedure G Page 123 On the MCAP Master Control menu bar click on the Settings menu bar option When the pulldown menu appears click on Remote Connect Settings then Com Port The display will now appear as in Figure 6 3 Settings v Connect to MCAP Disconnect from MCAP Local Connect Settings Remote Connect Settings PhoneNumber Password DSP Settings ComPort gt PASNE v Use Local MCAP Use Remote MCAP Y Enable Panel Input Level Controls Enable Panel Headphone Controls Figure 6 3 Remote Connect ComPort Selection Menu Now click on th
69. e operation EQ Range set to 10db Output Shape set to Flat 81 Figure 4 41 SIF with EQ Range set to 200p 82 Figure 4 42 SIF with EQ Range set to 50dB cece cece cece eeeeeeeeeeeeeeeeeeeeeeeeeeaaees 83 Figure 4 43 Attack Noise operation Attack Range set to 200p 84 Figure 4 44 Hi Res Graphic Filter Window 0 ceeeecceeeeeeeeeeeeeeeeeeeeeaeeeeeeeeeeeeeeeeeaaees 85 Figure 4 45 Hi Res Filter Store Window AEN 86 Figure 4 46 Hi Res Graphic Filter Recall Window eececeeeeseeeeeeeeeneeeeeeesneeeeeeneaes 87 Figure 4 47 New Hi Res Graphic Filter Display 87 Figure 4 48 Hi Res Graphic Draw in Progress seeseessssereeeeeseeerrrnrnreeseeerrrrnnnnnesene 89 Figure 4 49 Completed Hi Res Graphic Drauw 89 Figure 4 50 Hi Res Graphic Edit Window 0 eeeeeeeeeececceeeeeeeeeeeseeeeeeeeeeeeneenenseeeees 90 Figure 4 51 Hi Res Graphic Define Edit Region sssssssssssssirsrsssssrrrrrnrnrensserrrrrnnneneseee 90 Figure 4 52 Hi Res Edit In Progress EEN 91 Figure 4 53 Completed Hi Res Graphic Ed 91 Figure 4 54 Normalized Hi Res Graphic Elter 92 Figure 4 55 Tri Parametric GE 94 Figure 4 56 Graphical Representation of a Parametric Elter 95 Figure 4 57 Limiter Compressor Expander Control Window eeeeeeeeeeeeeeeeeteees 97 Figure 4 58 20 Band Graphic Equalizer Control Window ssssssssseeeneeeseeseerrrrnreeene 100 Figure 4 59 Dual Parametric Eiter 102 Figure 4 60 Spectrum Analyzer and C
70. ed and Control 9 16 Notches 9 16 displayed Used to switch the Multiple Notch filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the Multiple Notch filter and its controls follows in Figure 4 30 Attenuation dB lt a Bez Notch Width 1 Notch Width 2 Notch Width 16 4 4 11 Slot Filter Application Freguency Hz Figure 4 30 Multiple Notch Filter Graphical Description The Slot filter is used to isolate or slot a single frequency signal such as a tone or a whistle in the input audio attenuating all other audio This is the exact opposite of the Notch filter function C Page 69 To properly utilize the Slot filter you will first need to identify the frequency of the signal to be isolated this is best done using the Spectrum Analyzer window See Section 4 7 for complete instructions on operating the Spectrum Analyzer window Once the frequency of the signal has been identified initially set Stopband Attenuation to 60 dB and the Slot Width to the narrowest possible value Next set the Slot Frequency to the signal frequency Fine adjustment of the Slot Frequency may be necessary to
71. een identified set the Slot Freq uency of each slot to be used to the desired signal frequency Usually the signal frequencies will not remain constant but will vary slightly due to modulation wow and flutter and acoustic beating Therefore you may need to increase the Slot Width of each slot from its minimum setting to avoid having the signal move in and out of the slot Once all the Slot Freqs and Slot Widths have been entered you will need to build the actual filter using the Build command Like the Multiple Notch Filter this filter is also constructed in the computer A brief delay occurs after Build before it takes effect E x Slot Freq width Slot2 Freq width Slot3 Freq width Slot4 Freq width Out Hz Out Hz Out Hz Out Hz Build 4 L 4 4 d 4 53 Hz 53 Hz 53 Hz 53 Hz 4 D gt d 4 D Destroy Slot5 Freq width Slot6 Freq width Slot Freq width Slot8 Freq Width Control 9 16 Out Hz Out Hz Out Hz Out Hz 4 L 4 gt 4 d H L Filter In 53 Hz 53 Hz 53 Hz 53 Hz i m Zelle e Figure 4 33 Multiple Slot Filter Control Window Description of controls is as follows Slot Freq 1 16 Specifies frequency in Hertz which is to be isolated from the input audio by each of the 16 slots Minimum Slot Freq is 1 Hz while maximum Slot Freq depends upon the System Bandwidth setting Set Slot Freq to Out scroll box in ful
72. eference These basic setups should be able to enhance most voice recordings To begin processing audio with one of these setups recall the desired setup file by clicking on its filename in the Setup Files box then click on OK 11 When the mouse cursor returns to normal the setup file recall will be complete Toggle the MONITOR switch on the MCAP external processor between MAIN INPUTS and OUTPUTS to hear the difference between the unprocessed input signal and the processed output signal Feel free to experiment with the MCAP Master Control Panel settings you may recall the original setup at any time by repeating steps 8 12 If you wish to try loading any of the other basic setup files repeat steps 8 12 Once you become comfortable recalling the basic setup files it is strongly recommended that you complete the MCAP Tutorial in Section 3 2 3 2 MCAP Tutorial This brief tutorial should allow the user to quickly learn the basic operation of the MCAP s controls It should require about 1 hour to complete yet it demonstrates the basic functionality NOTE A subset of the MCAP s functions are utilized in this tutorial Refer to Chapter 4 MCAP SOFTWARE REFERENCE MANUAL for detailed information on all of the MCAP s functions Tutorial Steps 1 With the installation procedure in Section 2 2 completed run the MCAP Master Control program by double clicking the MCAP Master Control icon in Microsoft Windows A window similar to Figur
73. er Cle Fun eg Exponentiat TTT gi Hide Controls Print Close Figure 4 62 Spectrum Analyzer Window Description of controls indicators is as follows Averager Section Controls averaging of successive FFT spectral traces Mode selects the type of averager update to be used The available choices are Exponential Peak Hold and No Average Exponential averaging is normally used since it provides the smoothest display In this Mode the Num Averages scroll bar is displayed This bar selects the number of averages to be applied to spectral traces The more averages applied the smoother the displayed spectrum waveforms will be however the waveforms will also update more slowly as Num Averages is increased For voice filtering applications 8 to 32 averages are recommended the maximum Num Averages is 32768 Peak Hold averaging is useful when trying to detect momentary spikes in the frequency spectrum In this Mode the largest detected magnitude in each of the 920 frequency points is retained Since the spectrum does not automatically leak down with the signal it will be CGAY Page 105 necessary to periodically click on the Clear button when using this averager Mode No Average bypasses all averaging allowing the raw unaveraged FFT spectrum to be displayed The user can freeze an averaged trace by clicking the Run Freeze button between Run and Freeze The user may clear the averaged trace s and restart the
74. er and its controls follows in Figure 4 25 CGAY Page 62 Transfer Functions of a 60 Hz Comb Filter Having 40 dB Notch Depth and 300 Hz Notch Limit Attenuation dB All Harmonics Frequency Hz BW Attenuation dB Even Harmonics Frequency Hz I BW Attenuation dB Harmonics Frequency Hz I BW Figure 4 25 Comb Filter Graphical Description 4 4 8 Inverse Comb Filter Application The Inverse Comb filter is used to isolate everything but the harmonically related sounds sounds which have exactly equally spaced frequency components of interest such as power line hum constant speed motor generator noises etc from the input audio The filter response consists of a series of equally spaced slot filters This filter is the exact opposite of the Comb Filter described in Section 4 4 7 Adjust the Inverse Comb Frequency to the desired spacing between slots also known as fundamental frequency Set the Harmonic Limit to the frequency beyond which you do not want any more slots Set the Attenuation to the amount in CGAY Page 63 dB by which everything but the harmonically related slot frequencies are to be reduced Normally the Enhance Harmonics option will be set to All causing all but the frequencies at all multiples of the Fundamental Frequency within the Harmonic Limit to be reduced However certain types of noises have only the odd or even harmonic com
75. er the delay line is to go into either the filter Input channel or the selected Reference channel For most applications a slight delay typically 5 msec is placed in the Input channel For applications with long distances between the mike and radio TV a delay in the Reference channel may be required Extreme caution should be exercised when using reference channel delay excessive delay in that channel will not allow cancellation to take place Sets the number of audio samples in the delay line Delay is indicated both in samples and in milliseconds Minimum Delay is 1 sample but can be set to as high as 32768 samples depending on Configuration and Number DSP Stages settings Please Note If multiple Ref Canceller stages are placed in series only place delay in the Input channel of the first filter set all other stages Input delays to 1 sample as this delay will be propagated through the system to all subsequent stages However if Reference delays are used each Ref Canceller stage delay line will need to be configured separately Selects Auto matic or Fixed adaptation rate Auto is recommended When Fixed is selected the specified Adapt Rate Mu is applied to the filter at all times When Auto is selected the specified Adapt Rate is continuously power normalized depending upon the input signal level The Auto mode generally results in faster convergence for a given Mu 24 14 is an alternate means of expressing 214 0 000061 25
76. et to 60 000 Hz then selecting All will generate notches at 60 Hz 120 Hz 180 Hz 240 Hz 300 Hz etc Selecting Odd will generate notches at 60 Hz 180 Hz 300 Hz etc Selecting Even will generate notches at 120 Hz 240 Hz 360 Hz etc Used to switch the Comb filter in and out of the process without affecting the other filters in the process Button indicates Filter In CAS Page 61 when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel Hint A comb filter is adjusted in the following manner Set the Notch Limit and Notch Depth to their maximum positions set notch harmonics to All Next adjust the Comb Frequency to achieve maximum hum removal normally this will be in the vicinity of 60 or 50 Hz Analog recordings will seldom be exactly 50 or 60 Hz due to tape speed errors Next adjust the Notch Limit down in frequency until the hum is bearly heard then increase it 100 Hz Adjust the Notch Depth up following the same procedure Finally select the Odd or Even if they do not increase the hum level otherwise use All This procedure minimizes the filtering to only that needed for the hum Since a comb filter is a reverberator a 1CH Adaptive Filter is often placed after it to reduce the reverberation and clean up any residual noises escaping the comb filter A graphical description of the Comb filt
77. eventh button labelled Previous will cause the curve to be restored to the shape it had prior to the last memory recall at the current System Bandwidth setting Successive clicks of Recall then Previous perform A B comparison of two filter curves The New Edit and Normalize buttons are used to graphically manipulate the shape of the filter curve Their functions are complex and thus are best illustrated in the following mini tutorial 1 From the MCAP Master Control Panel set System Bandwidth to 5 4 kHz Configuration to Mono and Number DSP Stages to 2 Click on the Select button in the Filter 1 block then select Hi Res Graphic from the selection window 2 Click on the Control button in the Filter 1 block to bring up the Hi Res Graphic Filter control window When used for the first time the control window will be the that of the previous Figure 4 44 3 Click on the New button to draw a new filter The screen will now appear as shown in figure Figure 4 47 Figure 4 47 New Hi Res Graphic Filter Display Had you accidentally clicked the New button you could click on Abort to restore the previous filter G Page 87 The first mouse E click in the graph region determines the DC 0 Hz level g 3227 Hz Atten You should now notice that all the buttons on the control window have been replaced by a simple Abort botton Clicking on Abort at any time prior to completing the curve draw restores the previous filter
78. files previously stored by the Digital Audio Company PCAP software can be loaded by the MCAP software The PCAP Il software is also capable of operating the MCAP unit Store a setup to a disk file as follows 1 Click on File on the Master Control menu bar When the pulldown menu appears click on Save Setup File This will cause the window in Figure 4 64 to appear Normally it will not be necessary to change the Drive or the Directories settings if however you desire to place the setup file into a different drive such as a floppy drive or directory scroll through the lists of available drives and directories and select the desired drive or directory by double clicking it If you select a drive that is not ready an error message will be generated Each stored setup will have a time stamp and a user entered text Description to uniquely identify it The time stamp will be set automatically when the file is stored but you must enter the Description text before storing the file To enter or edit the Description text click on the Description text box and type in any text desired It is recommended that the text be descriptive of the setup s application CGAY Page 111 Description F Store in File Name dac C PROGRA 1 DIGITA 1 MCAPY40 Directories Drives acy c X JPROGRA 1 DIGITA 1 Cancel E Protect from future overwrite Figure 4 64 Store Setup File Window 4 You will need to spec
79. filter is being calculated When the calculations are complete the mouse cursor and the buttons in the Hi Res Graphic control window will return to normal appearance 6 Suppose you decide that you would like to make a change in a segment of the filter curve Click on Edit to bring up the following display CGAY Page 89 Select amount in dB by which to drop the trace prior to editing Click on Proceed to drop trace and continue edit or click on Cancel to abort NOTE If you select Proceed you will next need to define the portion of the trace to be edited by clicking on the left and right edges of the edit region Cancel Figure 4 50 Hi Res Graphic Edit Window In this window you can make the entire filter curve drop by a specified amount prior to editing the curve This can be used to create headroom which can be used to increase the gain decrease the attenuation in one portion of the curve relative to the rest of the curve For now select a drop of 0dB No Drop and click on Proceed You should now notice that all the buttons on the control window have been replaced with a single Abort button which permits returning to the pre Edit filter To edit the curve you will first need to define the edit region by carefully specifying the left and right edges of the portion of the filter curve that you wish to modify Click your mouse to the left and to the right of the desired region to produce the following display Figure 4 51
80. ge 38 Release Time gt Threshold C 0 125 o C 6dB 0 250 seconds 9dB C 0 500 seconds C 12dB C 1 0 seconds C 15dB Link C Independent Limiter Out CG Linked Figure 4 6 Limiter Setup Window Threshold specifies the input bargraph level which is considered to be an overload condition any time an input signal exceeds this level the gain will be decreased for that input until it no longer exceeds the Threshold The Threshold options are 6dB highest 9dB 12dB and 15dB lowest The 9dB setting is recommended for most applications In general Threshold settings lower than 9dB will provide better overload protection but with significant sacrifice in peak signal level dynamic range The Link option is provided in Stereo configurations to give the user the option of making the input channels Linked or Independent In Mono configuration the extra inputs are used only with the Reference Canceller and are always Linked When Linked the Limiter gains are equal at all times for all channels and are reduced in response to an overload on any input channel When Independent the Limiter gains are not necessarily equal each reduced in response to only its own input channel For stereo or multiple microphone applications the Limiter inputs should be Linked to avoid annoying Left Right differential gain shifts however Independent Limiter gains should be used when processing two unrelated monophonic signals
81. ger for printing For this feature to work properly a printer with paper needs to be connected to your computer 4 9 6 Getting Online Help Context sensitive online help is available to the MCAP Master Control program at any time by pressing the lt F1 gt key This is a standard feature of Microsoft Windows programs and is the recommended method for accessing help The term context sensitive means that the help text that is displayed depends upon the window from which you are currently operating For example if you are operating the Spectrum Analyzer controls and you press the lt F1 gt button help text for the Spectrum Analyzer will be displayed An alternative method for accessing help is to click on Help in the Master Control menu bar The following pulldown menu Figure 4 69 will be displayed CAY Page 116 ast Start Instructions About Master Control Program Fi A H ow To Print Screens Figure 4 69 Help Pulldown Menu Click on Contents to access the WinHelp utility Contents window The Contents window will display all the subjects for which help is available for the MCAP Master Control program You may browse through the displayed subjects and select help for a particular subject by double clicking the desired subject The WinHelp utility is a separate Windows program Once it has displayed the help text it will remain on the screen as a separate window until it is closed by the user For further information on t
82. h positions 1 3 to desired baud rate as follows d Replace top cover and reconnect all cables 9600 19200 38400 38400 default Table 6 1 Baud Rate DIP Switch Settings CAY Page 121 2 Next configure the MCAP Master Control program for the new baud rate as follows a Settings Make sure that the MCAP external processor is powered OFF initially Power ON the computer not the external processor and load Windows Run the MCAP Master Control program by double clicking the icon Click OK if any error messages occur Power ON the MCAP external processor On the MCAP Master Control menu bar click on the Settings menu bar option When the pulldown menu appears click on Local Connect Settings then Baud Rate The display will now appear as follows Figure 6 2 Click on the baud rate setting which corresponds to the MCAP external processor DIP switch settings To attempt connection through this port click on Settings then Connect to Local MCAP If any error messages appear recheck COM port setting Baud Rate setting connections and DIP switch settings Click on File then Exit to exit the MCAP Master Control program and save the new baud rate setting Connect to MCAP Disconnect from MCAP Local Connect Settings ComPort gt Remote Connect Settings BaudRate gt 9600 baud DSP Settings 14400 baud 19200 baud wv Use Local MCAP Use Remote MCAP v 38400 baud
83. hanges affect the filters operation First allow the filter to converge in Always and then click on If Output lt Threshold Adjust the G Page 45 Filter Size Note Increasing maximum size may cause subsequent stages to be reduced in size or dropped to Cancel accommodate extra taps threshold for adaptation by observing the bargraph levels when the voice is not present Click on the Clear button if you desire the filter to completely readapt based upon the new Conditional Adaptation settings Used to set the number of FIR filter taps in the adaptive filter Filter size is indicated both in taps filter order and in milliseconds Minimum Filter Size is 32 taps but it can be set to as high as 8192 taps depending on System Bandwidth Configuration and Number DSP Stages settings Normally the maximum filter size typically 1024 taps is used for the Ref Canceller adaptive filter To access larger adaptive filter sizes click on the Adjust Maximum Size button The following dialog box Figure 4 13 should appear Keep Maximum Size at 1024 taps C Increase Maximum Size to 2048 taps C Increase Maximum Size to 3072 taps Increase Maximum Size to 4096 taps C Increase Maximum Size to 5120 taps C Increase Maximum Size to 6144 taps C Increase Maximum Size to 7168 taps C Increase Maximum Size to 8192 taps Figure 4 14 Adjust Maximum Filter Size Window By default the current maximum adaptive filter size is selected clic
84. he WinHelp utility please consult your Microsoft Windows User s Guide CGAY Page 117 5 OPERATING MCAP STAND ALONE Before the MCAP external processor can be operated Stand Alone at least one of the Stand Alone setup memories must be programmed using the procedure in Section 4 9 3 Operate the MCAP external processor as a Stand Alone audio processor as follows 1 Switch the front panel OPERATION switch to the STAND ALONE position Connect 12VDC or 120 240VAC power and switch the POWER switch ON Connect the signals to be processed to the rear panel ANALOG MAIN INPUTS BNCs for most filtering applications For an AES EBU digital source connect the stereo digital signal to the DIGITAL MAIN INPUTS jack and set the MAIN INPUTS slide switch to DIGITAL If extra references are to be used connect them to the analog REF INPUTS Adjust the front panel input LEVEL controls for all ANALOG signal inputs such that the tricolor LEDs indicate GREEN most of the time with occasional YELLOW peaks Note The LEVEL controls do have effect on DIGITAL signal inputs so the must always be adjusted Connect a tape recorder to the rear panel LEFT and RIGHT ANALOG MAIN OUTPUTS BNGCs if recording the processed audio is desired If using a DAT the AES EBU DIGITAL MAIN OUTPUTS may also be used both the ANALOG and DIGITAL MAIN OUTPUTS jacks are hot at all times Plug stereo headphones into the front panel PHONES jack Adjust the VOLUME control to a
85. hen the Clear All button has no effect NOTE To individually clear any adaptive filter without disturbing other adaptive filters click on the Clear button in its Filter Box Toggle control used either to freeze all adaptive filters Adapt Disable displayed or to allow non frozen filters as specified by the Adapt Freeze button in each Filter block to adapt Toggle control used to specify whether the original input signal s is are routed to the line output s Processor Out displayed or CGAY Page 33 Coefficient Display Button Spectrum Analyzer Button Output Box Status Box whether the product s of the digital processor is are routed to the line output s Processor In displayed Allows user to quickly activate built in coefficient display see Section 4 8 Coefficient Display Window Allows user to quickly activate the built in spectrum analyzer display See Section 4 7 Spectrum Analyzer Window Used to view output signal levels via bargraph display setup the Output HPFs and switch them In and Out of the process setup output automatic gain controls AGCs and switch them In and Out of the process and to utilize the optional on screen Headphone controls See Section 4 2 Input and Output Processors for further details on the Output HPFs AGCs and Headphone controls Used to indicate RS232 COM port status The images that can be displayed by the Status Icon are EJ Selected COM port located and MCAP
86. highest slider is exactly OdB Once the equalizer is adjusted it should be normalized to minimize signal loss Click on the Make All OdB button to instantly set all the sliders to the OdB position The original slider settings would now be lost had we not previously stored them in step 36 Click on the Recall button to bring up the Recall 20 Band Graphic Equalizer window The window in Figure 3 13 will appear Click on the 1 button to recall the slider settings previously stored in Memory 1 The Previous button will recall the last settings in case you intended to but forgot to save them Once you have clicked this button the system will automatically return to the 20 Band Graphic Equalizer control window and the original slider settings will be restored from Memory 1 Click on OK to exit the 20 Band Equalizer Control Window Click on the Spectrum Analyzer button This will cause the Spectrum Analyzer window to appear as shown in Figure 3 14 The actual spectral display will depend upon the audio being processed Use the mouse to set up all controls as they appear in Figure 3 14 Make sure that the Primary In selection is highlighted in the Yellow Signal Select box that the Line Output selection is highlighted in the Blue Signal Select box and that Display is set to Both CAY Page 22 44 45 46 47 Click on desired memory or press cancel to exit ee 6 ala 3 8 zl 4 9 5 10 Previo
87. ify a filename for the setup Click on the Store in File Name text box then type the desired filename up to 256 characters All setup filenames must have the DAC extension thus the DAC extension is automatically included in the text box If you delete the DAC extension an error message will be generated 5 If you wish to protect your setup file from being accidentally overwritten in the future by the Save Setup File window click the Protect from Future Overwrite box This does not prevent deletion or overwrite by the Windows Explorer or by MS DOS 6 Click on OK to save the setup file with the selected filename to the specified drive and directory 4 9 2 Recalling Setups from Disk Files Application To save time configuring control settings in the MCAP Master Control program complete setups previously stored may be recalled from disk files with a few simple mouse Clicks This is particularly handy when making presentations which require multiple setups or when it is desired to precisely duplicate a previous enhancement procedure Also this feature allows easy transfer of enhancement setups between MCAP systems using floppy disks CAS Page 112 Note Any setup files previously stored by the Digital Audio Company PCAP software can be loaded by the MCAP software The PCAP Il software is also capable of operating the MCAP unit Recall a setup from a disk file as follows 1 Click on File on the Master Control menu bar When the
88. ilt in no external AC adaptor is required Up to thirteen stages of mono enhancement processing nine stereo stages including digital parametric equalizers Four analog signal inputs 1 PRI 3 REFs mono LEFT RIGHT LREF RREF stereo two analog signal outputs AES EBU digital audio interface with selectable digital output sample rate Path Correction delay lines on all four signal inputs to correct for gross delay mismatch ie satellite delays Dedicated D A converter for headphone output allowing non intrusive monitoring of any digital filter output All Windows based control versatile configuration and easy adjustment Controlled by a laptop or desktop computer minimum of 800x600 pixel display required Built in dual channel 920 line FFT spectrum analyzer with dedicated RS232 output Built in digital filter coefficient display Disk file storage recall of filter setups Stand alone operation allowing the MCAP to be operated at desired settings without PC Report generator for hardcopy printouts and word processor files of filter setups Unmatched flexibility and performance G Page vii The MCAP is applicable to a broad spectrum of voice and similar audio signals It attacks a wide variety of noises in forensic applications Body microphone cassette microcassette telephone broadcast and hi fi audio signals can all be processed efficiently since the MCAP can be set to operate at bandwidths of 3 2 5 4
89. imum elimination of high frequency noise The amount of volume reduction above the Cutoff Frequency can further be controlled by adjusting the Stopband Attenuation setting maximum volume reduction is 60dB The slope at which the volume is reduced from normal at the Cutoff Frequency to the minimum volume specified by Stopband Attenuation can also be controlled by adjusting the Transition Slope setting E EJ r Cutoff Frequency Stopband Attenuation 3500 Hz 60 dB a WT Transition Slope 1365 dB Octave E az Figure 4 16 Lowpass Filter Control Window Description of controls is as follows Cutoff Specifies frequency in Hertz above which all signals are attenuated Frequency Frequencies below this cutoff are unaffected Minimum Cutoff Frequency is 100 Hz while the maximum Cutoff Frequency depends upon the System Bandwidth setting Cutoff Frequency can be adjusted in 1 Hz steps CA Page 52 Stopband Specifies amount in dB by which frequencies above the Cutoff Attenuation Frequency are ultimately attenuated Stopband attenuation is adjustable from 10dB to 60dB in 1 dB steps Transition Specifies slope at which frequencies above the Cutoff Frequency are Slope rolled off in dB per octave Sharpest roll off occurs when Transition Slope is set to maximum while gentlest roll off occurs when Transition Slope is set to minimum Sharp rolloffs may cause the voice to sound hollow
90. in a Stereo configuration CA Page 39 4 2 4 Digitally Controlled AGC Application The dual output Automatic Gain Control automatically attempts to boost low level output signals to a peak reference level 18dB bargraph level by gradually increasing output signal gain over a specified Release Time interval until either the proper level or Maximum Gain has been reached This compensates for near party far party conversations and for losses in signal level which may have occurred during the enhancement process If the output signal levels are at or above the 18 dB reference level the AGC will have no effect Clicking on the AGC Button will cause its caption to toggle between AGC In and AGC Out as shown in Figure 4 7 indicating whether the AGC is in or out of the process Figure 4 7 AGC Button For fast access to the AGC pressing lt Alt G gt may also be used to toggle the AGC in or out of the process NOTE The AGC Button is overridden by the Processor button When the Processor button is set to Processor Out the AGC will be bypassed regardless of its button status y x m Release Time Maximum Gain C 50 milliseconds C 5dB CC 25dB C 100 milliseconds Ge 10dB 30dB 200 milliseconds C 15dB C 35dB C 400 milliseconds C 20dB Link AGC In C Independent CA Page 40 Figure 4 8 AGC Setup Window When the AGC Setup button is pressed The window in Figure 4 8 will appear This windo
91. ins to be affected achieving maximum elimination of low frequency noise The amount of volume reduction below the Cutoff Frequency can further be controlled by adjusting the Stopband Attenuation setting maximum volume reduction is 60dB The slope at which the volume is reduced from normal at the Cutoff Frequency to the minimum volume specified by Stopband Attenuation can also be controlled by adjusting the Transition Slope setting LS r Cutoff Frequency Stopband Attenuation Out Hz 10 dB 4 b 4 b Transition Slope Filter In 1 dB Octave 4 L Hi Figure 4 18 Highpass Filter Control Window Description of controls is as follows Cutoff Frequency Specifies frequency in Hertz below which all signals are attenuated Frequencies above this cutoff are unaffected Minimum Cutoff Frequency is 0 Hz no frequencies attenuated while the maximum Cutoff Frequency depends upon the System Bandwidth setting Cutoff Frequency can be adjusted in 1 Hz steps Stopband Specifies amount in dB by which frequencies below the Cutoff Attenuation Frequency are ultimately attenuated Stopband attenuation is adjustable from 10dB to 60aB in 1 dB steps CA Page 54 Transition Slope Filter Button Specifies slope at which frequencies below the Cutoff Frequency are attenuated in dB per octave Sharpest attenuation occurs when Transition Slope is set to maximum while gentlest attenuation occurs when
92. ion Com Port Com2 19200 Current Status Click on Auto Answer to allow phone access to MCAP Figure 8 3 PASSTHRU Program Main Screen The action button at the bottom of the Main Screen has different functions at different times and reflects what the program will do when the remote user clicks it As shown in the above figure the present label is Auto Answer The Current Status box always gives an explaination of the action button This button cycles through the the following labels G Page 129 Wait PASSTHRU is busy Wait until a different label appears Auto Answer Click on this action button to instruct the program to perform the steps necessary to automatically answer the phone Passthru D configure Set MCAP Port gt Set MCAP Baud Rate gt Set Modem Port b Set Modem Baud Rate gt Advanced Session Setup Set Entry Password About Figure 8 4 Configure Drop Down Menu Abort PASSTHRU is testing the remote MODEM and MCAP By clicking Abort the program will stop and wait for the remote user to select Auto Answer again After the devices are tested the program will begin monitoring the MODEM for ringing and automatically answer the phone Hang Up PASSTHRU has established a link to the Base Location Click to force the program to break the link by hanging up on the Base Location The program will wait for the remote user to select Auto Answer again 8 3 1 PASSTHRU Configure Drop
93. ity is also provided to allow the user to store commonly used equalizer shapes to disk memories so that they can be recalled later Description of operation The Spectral Graphic Equalizer operation is identical to the Hi Res Graphic Filter of Section 4 4 14 with the singular exception that its resolution is one fourth as great Please refer to this section for operating instructions and illustrations 4 5 3 Dual Parametric Equalizer The Dual Parametric Equalizer is identical to the Tri Parametric Filter described in Section 4 4 16 except that only two substages are available instead of three Please refer to that section for operating instructions x r input Atten Substage 1 Wide Gubstage 2 Wide Output Level 1 0dg Center Freq Center Freq DL o Width Width 6 0 1900 00 Hz 1800 00 Hz 12 l 2 E 24 Boost Cut Boost Cut 30 42 4 gt 4 L Master Out wb Sal OK Substage In ey goseesesoseee Ho Suggestion Adjust each substage separately with other substage clicked out Figure 4 59 Dual Parametric Filter 4 5 4 Limiter Compressor Expander This Equalizer is the same a s the Limiter Compressor Expander described in Section 4 4 17 See that section for full details CAS Page 102 4 6 DSP Display Selection 4 6 1 Spectrum Analyzer and Coefficient Display Buttons Coefficient Display Spectrum Analyzer Figure 4 60 Spectrum Analyzer and Coefficient Di
94. king on OK or Cancel at this point will exit the window without resetting the filter However selecting any of the other options increasing or decreasing the maximum size will cause all adaptive filters to be cleared and reset the currently selected filter to the new maximum size when the OK button is clicked Click Cancel at any time to exit the Adjust Maximum Size window without affecting any filters Please Note Any time the maximum size of any adaptive filter is increased the Number DSP Stages options may be reduced and subsequent filter stages may be dropped due to the MCAP s physical CAS Page 46 Adapt Rate Delay Channel Delay Auto Fixed Mode limitation of 8192 total filter taps for all filters When this increase occurs the Oversized Filters caption will appear in the Number DSP Stages block Therefore the user should strive to minimize the sizes of all adaptive filters used in order to maximize the number of available filter stages Used to set the rate at which the adaptive filter adapts to changing signal conditions mathematically known as Mu A Mu of 1 x 2 provides very slow adaptation while a Mu of 5884 x 2 provides fastest adaptation As a rule set this rate to 256 x 2 initially to establish convergence then back off to a smaller value to maintain cancellation Warning Be careful when using Adapt Rates larger than 256x2 as the instability could cause the filter to crash Specifies wheth
95. l left position if the slot is not desired Slot Freq is adjustable in 1 Hz steps Slot Width 1 16 Specifies width in Hertz for each of the 16 slots Minimum and maximum Slot Widths and adjustment resolution depend upon the System Bandwidth setting CGAY Page 72 Build Button Destroy Button Control Button Filter Button Causes the FIR filter coefficients for the Multiple Slot filter to be calculated and downloaded to the MCAP external processor for implementation While this is occurring an hourglass mouse cursor will appear NOTE You must click the Build button after any Slot Freq or Slot Width is changed in order for the change to take effect You must also click the Build button after any change in System Bandwidth Configuration or Number DSP Stages in order to rebuild the filter Clears all Slot Freq and Slot Width settings for all 16 notches and restores the Multiple Slot filter coefficients to an allpass filter no slots The Multiple Slot control window is only capable of displaying the settings for eight slots at a time Slots 1 8 or Slots 9 16 may be displayed Click on the Control button to toggle between Control 1 8 Slots 1 8 displayed and Control 9 16 Slots 9 16 displayed Used to switch the Multiple Slot filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the pr
96. lay area Spectra are displayed in Cartesian X Y format with the Y axis representing magnitude in dB and the X axis representing frequency in Hertz A green grid is superimposed on the black background to assist the user in visually judging frequency and magnitude of spectral components A vertical red marker is used to read out the exact magnitude s Mag of any frequency Freq in the spectrum display To move the marker simply click the mouse cursor on the desired point in the Spectrum Display area or utilize the controls in the Marker Block described above Note The Spectrum Analyzer window is sizeable and can be expanded to full screen resolution by clicking on the Maximize button in the upper right hand corner of the display Selecting the Hide Controls option makes all screen controls in CGAY Page 107 visible allowing more screen area to be used for the Spectrum Display To reaccess the controls simply click on Hide Controls again to deselect the Hide Controls option Close Button Clicking on this button turns off the Spectrum Analyzer display 4 8 Coefficient Display Window Application In setting up a Ref Canceller filter it is sometimes useful to display the impulse response filter coefficients of the filter Additionally it is sometimes desirable to know the precise time domain response ie to determine delay of any of the digital Filter stages For these reasons the Coefficient Display window has been p
97. le Requires Windows 95 98 NT desktop or laptop system with CD ROM minimum 800 x 600 screen resolution and at least 50 MB free hard disk space At least on free RS232 COM port required for connection to MCAP USB adapter available Signal Processing Functions Adaptive Filters e Adjustable Filters Special Filters e Equalizers Misc e Other Processing e Path Delay e Spectral Analysis e Mono 1CH 2CH 3CH ACH Stereo 1CH 2CH Lowpass Highpass Bandpass Bandstop Notch Slot Comb and Inverse Comb Hi res graphic filter Stereo spectral inverse filters SIF 20 band graphic spectral graphic and parametric Compressor Expander also available in all positions Microprocessor controlled stereo limiter on analog inputs Output digital automatic gain control Adjustable four channel macro delay for gross signal delay line compensation Adjustable in one sample steps to 512k samples 43 seconds max at D Ak BW Dual channel 70dB dynamic range display 920 line resolution both on Master Control display and dedicated PC display via separate RS232 port Specifications subject to change without notice CAY Page 138
98. le in the Filter block for each filter on the Master Control Panel Hint A notch filter is best for stable tones It has a sharp bottom If a flatter bottom stopband is needed the bandstop filter Section 4 4 6 may be prefered Also a 1CH Adaptive filter Section 4 4 2 is useful in tracking varying tones A graphical description of the Notch filter and its controls follows in Figure 4 28 CAY Page 66 Attenuation dB Notch Width Notch Frequency Frequency Hz Figure 4 28 Notch Filter Graphical Description 4 4 10 Multiple Notch Filter Application The Multiple Notch filter is used to remove or notch out up to 16 single frequency noises such as tones or whistles from the input audio with minimal effect to the remaining audio This is accomplished using a frequency sampling synthesized 1024 tap FIR filter which is calculated in the PC by the MCAP Master Control program The Multiple Notch filter unlike the Notch filter is able to tolerate moderate wow and flutter variances in the frequency of a noise source if the frequency of a noise source varies excessively then the 1CH Adaptive filter is recommended To properly utilize the Multiple Notch filter you will first need to identify the noise frequencies this is best done using the Spectrum Analyzer window See Section 4 7 for complete instructions on operating the Spectrum Analyzer window Once the noise frequencies have been identified set the No
99. me Initialization Only 1 Turn off power to the remote PC MCAP and MODEM Connect the MCAP to the remote PC with a serial cable Connect the MODEM to the remote PC with a serial cable Connect the MODEM to the phone line Turn on power to the PC MCAP and MODEM After Windows is running double click the PASSTHRU icon to start the PASSTHRU program Verify the com port and baud rate for the MCAP change if necessary Verify the com port and baud rate for the MODEM change if necessary CAY Page 132 9 Click on Configure then Set Entry Password and enter a password After 1 entering the password click on OK to exit this screen 0 Click Exit on the menu bar to exit PASSTHRU and store the newly entered information 8 4 3 Remote Location Normal Operation Each Session Start Program 1 2 Verify the MCAP and MODEM are connected to the remote PC Verify the MODEM is connected to the phone line Turn on power to the PC MCAP and MODEM Start Windows and verify the MCAP Master Control program is not running on the remote PC Double click on the PASSTHRU icon to start the program Click on the Auto Answer button on the PASSTHRU Main Screen After PASSTHRU tests the MCAP and MODEM the Current Status box states that the program is waiting for the base user to call If any other message is displayed correct the problem and then return to step 4 above PASSTHRU now monitors
100. menu bar option then click on Exit Please refer to Chapter 4 0 for more detailed instructions on using the windows in the MCAP Master Control program CAY Page 28 3 3 Training CD Recording The MCAP Training CD supplied with the MCAP is a useful training tool Each of its 13 noise sample recordings is accompanied by a suggested Setup File installed on your comptuer along with the other MCAP software by the installation procedure Table 3 1 summarizes the contents of the training CD The SETUP column contains the name of the setup file installed on the disk as part of the MCAP software installation procedure Section 2 2 To access a setup file click on File in the Master Control menu bar or press lt Alt F gt Next click on Open Setup File or press lt Alt O gt The available setup files should then appear in the Setup Files box setup files have the extension dac If the needed setup file is not displayed the Drive or Directories may require changing Refer to Section 4 9 2 for additional details According to Table 3 1 the setup file sO3 dac is the suggested setup file for track 3 voice plus swept tones In all cases the name of the proper setup file for a particular training track is in the form sXX dac where XX is the track number All recordings except track 13 are monophonic i e the left and right channels have the same audio The 13th recording is a 2CH adaptive Ref Canceller filtering example and has the micro
101. n of operation CAY Page 92 The 20 Band Graphic Filter operation is identical to the 20 Band Graphic Equalizer of Section 4 4 14 Please refer to this section for operating instructions and illustrations 4 4 16 Tri Parametric Filter Application The Tri Parametric Filter is a three substage adjustable IIR filter which can be used for both peaking and nulling portions of the input signal s frequency spectrum Controllable parameters for each seriesed substage include Center Frequency Width and Boost Cut Typically parametric equalizers are used as notch filters which perform nulling of the input signal at a specified Center Frequency over a specified width The Boost Cut parameter can be set to a negative value 10B to 60dB for this type of operation However the parametric filter is also capable of peaking which allows a positive gain Boost Cut of 1dB to 16dB to be placed at the Center Frequency over the specified Width Each filter provides three peaking or nulling stages that can be configured independently Each substage can be independently bypassed using the Substage In Out buttons in order to allow the user to more quickly and easily adjust each stage for optimum results Simply click in the substage that is to be adjusted while the other stages are clicked out repeat this process for each substage that is used Also an input Input Atten control allows the user to quickly reduce the overall gain of the entire parame
102. nd of the audio before completing the tutorial please restart it some CD players allow a track to be continually repeated With the demonstration audio playing slowly increase the headphone VOLUME until audio can be clearly heard Click on the Filter button in both the Filter 1 block and the Filter 2 block until both buttons indicate Filter Out bypassed Click on the Equalizer button in the Equalizer block until the button indicates Equalizer Out bypassed Switch the MONITOR switch on the MCAP external processor to the OUTPUTS position Readjust the headphone VOLUME if necessary Switch the Input HPF in and out by clicking on the Input HPF button in the Input Levels block You should hear the low frequency effects of this control Restore the button to the Input HPF Out indication Switch the Output HPF in and out by clicking on the Output HPF button in the Output Levels block You should hear the low frequency effects of this control Restore the button to the Output HPF Out indication Click on the Limiter Setup button in the Input Levels block The following window Figure 3 5 will appear CGAY Page 15 r Release Time Threshold C 0 125 seconds C 6dB 0 250 seconds 208 C 0 500 seconds C 12dB C 1 0 seconds C 15dB Link Independent el ei Figure 3 5 Tutorial Limiter Setup Window Use the mouse to set the Release Time to 0 250 seconds and the Threshold to 9dB as sh
103. nd software the user must have a good working knowledge of IBM PC compatible computers and the Microsoft Windows operating environment Particularly the user must know which RS232 COM ports are COM1 COM2 COMS etc Usually a serial mouse will be installed on COM1 leaving COM2 available for connecting the MCAP external processor If COM2 is not available in the user s PC it will be necessary to reconfigure the MCAP software COM port selection by performing the procedure in Section 6 1 after completing the installation procedure in Section 2 2 The Microsoft Windows operating environment must be in place prior to installing the MCAP All video drivers device drivers etc must be installed and operating properly For advanced users who need to configure the MCAP to operate at RS232 symbol rates slower than 38400 baud factory default please see Section 6 2 Note Altering the baud rate setting is not recommended 2 2 Installation Procedure 1 Carefully remove the MCAP external processor from the shipping container Confirm that the AC power cord RS232 cables 2 demonstrator audio CD and software disk s are included Also confirm that any optional accessories are included 2 Make sure that the OPERATION switch on the MCAP front panel is set to the PC CONTROL position 3 Connect the AC power cord to the MCAP rear panel AC POWER connector Keep the POWER switch OFF for now 4 With the MCAP POWER switch OFF plug the AC power c
104. nge to OVL analyzer overload and the captions at the bottom of the Filter Display area to change color to red Specifies whether SIF is to be used to Equalize Voice or Attack Noise When Equalize Voice is selected the SIF control window appears as shown in Figure 4 36 When Attack Noise is selected the SIF Control Window appears as shown in Figure 4 37 Equalize Voice operation is used to reshape the original input voice audio to a more natural sounding spectral shape over a specified frequency range All audio outside this frequency range is attenuated by 40dB Attack Noise operation is used to attack large magnitude narrow band noises such as motor noises over a specified frequency range Audio outside this frequency range remains unaffected 0dB attenuation For Equalize Voice operation specifies EQ Range and Gain For Attack Noise operation specifies Attack Range and Gain EQ or Attack Range specifies the maximum amount of volume reduction that can be applied by the inverse filter within the specified frequency limits this may be set to the approximate difference in amplitude between the largest and smallest input spectral components within the frequency limits Maximum Range is 50dB NOTE Maximum Range should only be used when necessary it may excessively elevate background noises For Equalize Voice operation the inverse filter response rolls off to 40dB outside the frequency limits For Attack Noise operation the
105. nly RIGHT If you wish at this point to discontinue the Fast Start procedure and experiment with the MCAP Master Control Panel on your own please feel free to do so you will not damage anything If however you still feel unsure of what to do please continue the Fast Start procedure as follows 8 From the MCAP Master Control Panel menu bar click on File This will cause the following pulldown menu to appear Figure 3 2 CAY Page 11 il New Filter Configuration Save Setup File T bh Open Setup File View File Description Exit Figure 3 2 Fast Start File Pulldown Menu 9 Click on Open Setup File to bring up a window similar to Figure 3 3 Setup Files Drives HUMBUZ2 DAC Sc Directories CE IJ PROGRA 1 JDIGITA 1 MCAPV40 Description AC HUM REMOVAL Date 0734 Thu 23 Feb 1995 Figure 3 3 Fast Start Recall Setup Window 10 The Setup Files box should contain a list of all MCAP setup files on your hard disk The installation procedure in Section 2 2 should have installed several setup files which have the DAC extension onto your hard disk Included in these setup files are PHONE DAC Telephone audio enhancement BODYMIKE DAC Body microphone recorder audio enhancement HUMBUZZ DAC 5 Powerline hum and buzz removal REVERB DAC Cancellation of room echoes and reverberations G Page 12 RADIOTV DAC Cancellation of radio and or TV audio from live or recorded audio using a r
106. o Selects Residue or Predict output The Residue output is the normal output selection which is the signal left over after the predicted noise signal has been subtracted from the input signal The Predict output is the predicted noise signal Used to switch the 1CH Adaptive filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process Used to freeze this adaptive filter independently C Page 50 Button Clear Button Used to reset the coefficients of the 1CH Adaptive filter to zero without affecting any other adaptive filters in the process NOTE The Filter Clear and Adapt Freeze buttons are also available in the Filter block for each filter on the Master Control Panel CGAY Page 51 4 4 3 Lowpass Filter Application The Lowpass filter is used to decrease the energy level lower the volume of all signal frequencies above a specified Cutoff Frequency thus reducing high frequency noises such as tape hiss from the input audio The Lowpass filter is sometimes called a hiss filter The Cutoff Frequency is usually set above the voice frequency range so that the voice signal will not be disturbed While listening to the filter output audio the Cutoff Frequency can be incrementally lowered from its maximum frequency until the quality of the voice just begins to be affected achieving max
107. o allow setup files to be recalled from any directory of any drive Click on each file listed in the Setup Files list box Notice how the Description and Date for each appears at the bottom of the window as each is clicked Click on PHONE DAC then click on OK to recall the recommended settings for processing telephone audio If you do not have a printer installed on your computer skip now to step 66 Access the hardcopy report generator by clicking on ReportGenerator in the menu bar The pulldown menu shown in Figure 3 19 will appear CGAY Page 27 65 Make sure your printer is ready then click on Print Report to Printer A report listing all screen settings for the telephone filter setup will now be printed 66 Recall your original filter settings by repeating steps 61 and 62 to bring up the Open Setup File window Next click on OK in the Setup Files list box then click on OK to return to the Master Control Panel ReportGenerator Print Report To Printer Print Report To Eile Append Report To File How To Print Screens Figure 3 19 Tutorial Report Generator Pulldown Menu This completes the MCAP Tutorial Please feel free at this point to experiment with the on screen filter settings Remember you can always recall filter settings that will likely work using the Open Setup File feature To exit the MCAP Master Control Panel either double click on the X button at the upper right corner of the window or click on the File
108. o specifies the spectral range to be equalized using upper and lower frequency limits audio outside these limits is attenuated The amount of spectral correction range can also be controlled CAY Page 74 Original Audio Power Spectrum Frequency Spectral Inverse Filter Curve Frequency Resultant Audio Power Spectrum gt Frequency Figure 4 35 Basic Process of Spectral Inverse Filter The equalization effect of SIF is very beneficial with reverberant audio and recordings exposed to substantial recorder wow and flutter The noise sources must remain stationary for SIF to be effective SIF cannot readjust itself to changing noises such as music In such cases the 1CH adaptive filter is recommended A second SIF equalization mode is Attack Noise This mode is especially useful in reducing band limited noises such as horns and mechnically induced noises The operator isolates the spectral region where the noise is present with limit cursors and the noise is precisely flattened Audio outside these limits is unaffected CGAY Page 75 EJ Analyzer 32 m Filter Operation EQ Range Gain Jj_Run _ 6 in Range 13 dB Build OdB GG Equalize Voice d Num Averages C Attack Noise Gain 16 a Filter In O j gt ru Store Lower Voce Limit Upper Yoice Limit Output GH 1758 Hz 5678 Hz C Flat GG Voice Recall Ad o EL uL wl MI C Pink ol 8086 Hz Figure 4 36 SIF
109. ocess NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the Multiple Slot filter and its controls follows in Figure 4 34 Attenuat Slot on dB Width 1 Slot Wid ot Width 16 ra Frequency Hz Figure 4 34 Multiple Slot Filter Graphical Description CGAY Page 73 4 4 13 Spectral Inverse Filter Application The Spectral Inverse Filter SIF is an equalization filter which automatically readjusts the signal spectrum to reduce noise and muffling effects It is especially useful where the voice has been exposed to reverberations and bandlimited noises SIF measures the signal s spectrum and uses this information to implement a high resolution digital filter for correcting spectral irregularities and reduce added noises Figure 4 35 illustrates the process The original audio spectrum top trace is inverted middle trace A digital filter is implemented which has the shape of this middle trace When the original spectrum top trace is modified by this filter low energy frequencies are boosted and high energy frequencies are attenuated The resulting filtered audio has a flat or white spectrum of the bottom trace This mode of operation is Equalized Voice Available controls permit the operator to reshape the output audio to white shown pink or voice like spectrum The operator als
110. oefficient Display Buttons 103 Figure 4 61 Display Select Wmdow un 103 Figure 4 62 Spectrum Analyzer Wumdow 105 Figure 4 63 Coefficient Display Wmdow A 109 Figure 4 64 Store Setup File Wmdow AEN 112 Figure 4 65 Recall Setup File Window ccesseeneeesesseeeeeseeseeeeeesesseneeeeeesseeseneenes 113 Figure 4 66 Stand Alone Pulldown Men AAA 115 Figure 4 67 Auxiliary Switch Function Window 00 cc ccceeeeeeeeeeeeeeeeeeeeeeeeeeteneeeeeeeee 115 Figure 4 68 ReportGenerator Pulldown Men 116 Figure 4 69 Help Pulldown MenU E 117 Figure 6 1 ComPort Selection leese ebe eh 120 Figure 6 2 BaudRate Selection Men 122 Figure 6 3 Remote Connect ComPort Selection Men 124 Figure 6 4 Modem Phone Number Password Window eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 124 Figure 8 1 System Configuration EE 127 Figure 8 2 PASSTHRU Program ICOn ccccceeeeeeeeeeeneeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeeenaaees 128 Figure 8 3 PASSTHRU Program Main Green 129 Figure 8 4 Configure Drop Down Menu 130 Figure 8 5 Advanced Session Setup SCreen ce ccccessenceeeeeseeeeeesessenseeseesseeeeneees 131 Figure 8 6 Set Entry Password EE 131 CAY Page vi FOREWORD The MCAP Multi Channel Audio Processor is a new and powerful digital audio processor The MCAP offers the following advantages over other PC based audio processors Compact rack mountable packaging Both 9 18 VDC and 110 220 VAC 50 60Hz auto sensing supplies are bu
111. ol Panel Features ee 31 Figure 4 2 Path Delay Window kee 35 Figure 4 3 Input and Output HPF Buttons 37 Figure 4 4 Input HPF Setup Wumdow ENEE 37 FigUre4 5 Limiter BUTON E 38 Figure 4 6 Limiter Setup Wimndow sek 39 Figure ALP AGG e EE 40 Figure 4 8 AGC Setup Wmdow cece eeeeeeeeeeaaaeeeeeeeeeeeeeccaaaaeeeeeeeeeeeeeeenaaees 41 Figure 4 9 Headphone Control Wumdow ee 42 Figure 4 10 Filter Selection Wmdow ENEE 43 Figure 4 11 Filter Select Combo BOX ENEE 43 Figure 4 12 Equalizer Selection Wmdow en 44 Figure 4 13 Ref Canceller Filter Control Wmdow AAA 45 Figure 4 14 Adjust Maximum Filter Size Wimdouw 46 Figure 4 15 1CH Adaptive Filter Control Window ssssssssssnsnssssssssnrnrnrnnseererrnnnnnnesee 49 Figure 4 16 Lowpass Filter Control Window cceeeeeeceeeneeeeeeeeeeeeeeeeaeeeeeeeeeeeeeeeeeaaees 52 Figure 4 17 Lowpass Filter Graphical Description c cccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeaeees 53 Figure 4 18 Highpass Filter Control Wumdow sssssesssssessssennrnressseenrrnnnrnssseerrnnnnnnneseee 54 Figure 4 19 Highpass Filter Graphical Description ssssssssnnneeeeeeeeennrnnneesseerrrrrnnnnnesee 55 Figure 4 20 Bandpass Filter Control Window cccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeteeeeeeaaees 56 Figure 4 21 Bandpass Filter Graphical Description cccceeeeeeeeeeeeeeeeeeeeeeeeteeeeenees 58 Figure 4 22 Bandstop Filter Control Window AAA 59 Figure 4 23 Bandstop Filter Graphical Description
112. ons Since the SIF is an attenuator the audio level should be restored with the Gain scroll bar Normally setting this to one half the Range is adequate If output distortion occurs reduce the Gain The Gain may be increased to make up for losses in signal level due to previous Filter stages Note that the Gain is usually 0 dB in the Attack Noise mode Output Shape Three output spectral shapes are selectable by the user The Flat shape requires the SIF to produce a uniform to the degree possible long term output spectrum This can be subsequently reshaped by the Hi Res Graphic Filter or Output Equalizer to a more natural sounding spectrum Alternately the Voice or Pink shapes may be selected which have built in output shaping The Pink shape is often the most pleasing Experiment Select a section of audio and display its spectrum Freeze the analyzer and vary different control settings storing built filters Compare the results and determine the best solution Always compare these different filter solutions using the same input audio CGAY Page 84 4 4 14 Hi Res Graphic Filter Application In some applications it may be necessary to precisely reshape the spectrum of input audio prior to passing it through successive DSP filter stages For example if the audio is from a microphone which has an unusual frequency response curve for example a microphone acoustically modified as a result of concealment a compensation filter that resh
113. ontrol program is written to be run on any Microsoft Windows 95 98 NT IBM PC compatible computer For best performance the following minimum system is recommended Intel Pentium CPU processor at least 166 MHz 32 Megabytes of RAM 2 1 GB hard disk drive CD ROM Drive 800x600 color SVGA display with 0 28 or better dot pitch Two button mouse At least one spare RS232 port Laser or dot matrix printer Performance will improve with higher speed CPUs CAY Page 1 1 2 External Processor Capability The MCAP EXTERNAL PROCESSOR unit is a high performance self contained digital signal processor and contains 49 DSP microprocessors which are allocated as follows e Thirty two FIR filter processors which can be configured as a single 8192 tap adaptive digital filter or up to 8 1024 tap independent audio processors These flexible processors may be combined into mono and stereo configurations Any of the processors may be configured as an adaptive or adjustable digital filter e Two FIR fixed filter processors which are dedicated as output spectral equalizers e Two 65536 times oversampling FIR filter processors which allow the AES EBU digital audio input sample rate to be converted to the MCAP s sample rate for processing then back to the specified AES EBU digital audio output sample rate for recording onto a DAT e Three FIR fixed filter processors which perform up to 4X oversampling for the analog inputs and outputs e Six FIR fixed
114. operation specifies Lower Attack Limit and Upper Attack Limit These are the lower and upper frequency limits over which noise in the input audio is attacked These values should be set to bracket any noise spikes in the original audio power spectrum CAY Page 78 To set the upper and lower frequency limits use the horizontal scroll bars to position the two red markers on the Filter Display to the desired frequency positions NOTE You must use the scroll bars you cannot click the mouse at the desired points in the Filter Display area Output ShapeSpecifies the final reshaping curve to be applied to the entire SIF Block Build Button Filter Button Store Button filter For Attack Noise only Flat should be used For Equalize Voice three curves are available and include Flat no reshaping Voice 6dB octave rolloff above and below 500 Hz and Pink 3dB octave rolloff above 100 Hz The Voice and Pink curves are provided to reshape the resultant audio power spectrum to that of a typical voice spectrum the Voice curve provides hard reshaping while the Pink curve provides softer reshaping of the spectrum Builds the spectral inverse filter based on the original input audio spectrum and the SIF control settings When clicked the mouse cursor will change to an hourglass shape indicating that the PC is busy calculating the spectral inverse filter coefficients and sending them to the external processor When the filter buil
115. or the right side of the Coefficient Display grid to pan left or right Coefficients are displayed in Cartesian X Y format with the Y axis representing Value in a range from 1 0 to 1 0 The X axis represents Time in seconds A yellow grid is superimposed on the black background to assist the user in visually judging Time and Value of Filter coefficients A vertical red marker is used to read out the exact Value and Time of any Filter coefficient To move the marker simply click the mouse cursor on the desired point in the Coefficient Display area or utilize the controls in the Marker Block described above Selecting the Hide Controls option makes all screen controls in visible allowing more screen area to be used for the Coefficient Display To reaccess the controls simply click on Hide Controls again to deselect the Hide Controls option Clicking on this button turns off the Coefficient Display CGAY Page 110 4 9 Master Control Pulldown Menus 4 9 1 Storing Setups to Disk Files Application To save time configuring MCAP control settings complete setups may easily be stored to disk setup files for future recall These files are particularly handy when making presentations which require multiple setups or when it is desired to precisely duplicate the enhancement procedure at some point in the future Also this feature allows easy transfer of enhancement setups between MCAP systems using floppy disks Note Any setup
116. ord into an AC outlet 5 With the computer turned OFF connect the supplied RS232 cable between the CONTROL PC RS232 connector on the MCAP rear panel and the desired computer COM port You may need to purchase an adaptor if the COM port has 25 pins 6 Now that they are connected together switch ON both the MCAP and the computer CGAY Page 6 Once Windows has booted up Windows 95 98 or NT insert the MCAP Master Control software CD into the CD ROM drive in your PC The installation program should automatically run If not use the Run command in the Windows Start menu to start the installation program If the machine you wish to install the MCAP Master Control Software does not have a CD ROM drive please contact Digital Audio Company for installation software on diskettes The MCAP Setup Utility will now install the MCAP Master Control software on your PC s hard disk Please follow any instructions displayed by the Setup Utility Once the Setup Utility has completed installing the software the icon in Figure 2 1 should appear on your screen Figure 2 1 MCAP Master Control Icon Double click on this icon now to run the program A screen similar to Figure 2 2 should appear G Page 7 File Settings View Stand Alone ReportGenerator Help Input Levels System Bandwidth Left Filter 1 Right Filter 1 Output Levels Left Right LRef RRef C 3
117. ored in the Stand Alone memories 2 Click on Stand Alone on the Master Control Panel menu bar to access the following pulldown menu Figure 4 66 CGAY Page 114 Stand Alone Memory Memory2 Memor Memory4 Figure 4 66 Stand Alone Pulldown Menu 3 Click on the selected memory The following window Figure 4 67 will now appear Select desired function of STAND ALONE AUX switch on front panel Click on OK to program switch Note AUX switch if enabled will override screen control setting Does nothing disabled Toggles AGC In and Out Toggles Limiter In and Out C Toggles Output HPF In and Out Toggles Input HPF In and Out Toggles Right Channel Adapt Freeze Figure 4 67 Auxiliary Switch Function Window This window allows the function of the AUX switch on the MCAP external processor front panel to be programmed Click on the program option desired then click on OK 4 A message window will now appear to alert you that the previous contents of the selected memory will be lost and that 30 seconds could be required to transfer all settings to the memory Additionally the window will suggest that you also store your setup in a disk file Click on Yes if you wish to proceed or click on No to cancel without affecting the current memory contents An hourglass cursor will now appear indicating that the MCAP is busy storing the setup in the selected Stand Alone memory For complete instructions on operating the
118. ow release time are used with speech Setting a fast attack time less than 10 milliseconds causes the processor to rapidly respond to sharp sounds The level detector will be more peak sensitive to fast attack time and more average value sensitive to longer attack times An Attack Time of 2 5 milliseconds is recommended for Speech applications Short release times less than 100 milliseconds may make the level detector too responsive to intra syllabic pause creating an annoying pumping artifact Conversely long release times greater than 500 milliseconds for example may fail to respond to breath group pauses and exchanges between speakers Therefore a Release Time of 200 400 milliseconds is generally recommended for speech applications The gain algorithm dynamically adjusts the signal amplification based on input signal level and its Gain Region limiting compression or expansion If the input signal level exceeds the Limit Threshold it is in the Limit region If the input signal level exceeds the Compression Threshold but not the Limit Threshold it is in the Compression region And lastly if the input signal level is below the Compression Threshold it is in the Expansion region The three Gain Regions are described below Limit Region In the limit region the output signal level is damped or kept from exceeding the specified Limit Threshold by applying attenuation Compression Region In this region the output signal
119. own in Figure 3 4 Do not set up the Filter blocks and Equalizer blocks at this time 3 Connect the LEFT and RIGHT outputs AUDIO OUT jacks of a audio player to the LEFT and RIGHT ANALOG MAIN INPUTS jacks on the MCAP external processor Note Make sure that the MAIN INPUTS switch on the rear panel is set to ANALOG Insert the MCAP Training CD and rewind to the beginning Additionally the control buttons may be selected with the lt Tab gt key highlighting that button Once selected the button may be toggled with the lt Space gt or lt Enter gt keys Fast keys are also available for buttons having an underlined letter Pressing lt Alt gt in combination with the letter causes that button to toggle e g pressing lt Alt P gt toggles the Processor In Out button CA Page 14 Connect a pair of stereo headphones to the PHONES jack on the MCAP external processor Switch the MONITOR switch to MAIN INPUTS switch the SELECT switch to LEFT and adjust the headphone VOLUME control to MIN Mono headphones should not be used Play the demonstration audio Adjust the MAIN INPUTS level knobs on the MCAP so that the peak audio level as measured by the bargraphs is approximately 6 dB Alternately click on Settings then uncheck Enable Panel Input Level Controls to use the input level sliders on the MCAP Master Control Panel instead of the front panel knobs NOTE The audio needs to be playing throughout this tutorial If you reach the e
120. own in Figure 3 5 Click on OK when done Adjust the headphone VOLUME control to MIN Adjust the inputlevels to maximum This should cause the MCAP audio inputs to overload this will not damage the unit but will distort the audio The tricolor level LED should indicate RED on peaks and the Left bargraph in the Input Levels block should be frequently popping up into the RED zone indicating overload Slowly increase the headphone VOLUME until distorted audio can be clearly heard Switch the Limiter In and Out by clicking on the Limiter button in the Input Levels block You should notice the indicated bargraph levels decrease to 9dB and the audio quality as heard through the headphones dramatically improve whenever the button indicates Limiter In The input limiter is electronically lowering the INPUT LEVEL to avoid overload Restore the button to the Limiter Out position and restore the input levels to normal Click on the AGC Setup button in the Output Levels block The following window Figure 3 6 will appear If you try to click anywhere on the Master Control Panel while a control window such as the Limiter Setup window is displayed a warning beep will sound indicating that you need to first close the control window by clicking the OK button G Page 16 20 Release Time C 50 milliseconds C 100 milliseconds Ge 200 milliseconds C 400 milliseconds Maximum Gain C bd C 25dB perecevsvessoees C 15dB 35dB C 20dB
121. phone audio on the left channel and the TV reference audio on the right channel Playback the CD on a standard CD player connecting its Left and Right Line Outputs to the MCAP s LEFT PRI and RIGHT REF ANALOG MAIN INPUTS respectively As each track is played recall the suggested setup file sXX dac Try varying individual control parameters to observe overall processing effects G Page 29 TRACK TIME NOISE SETUP COMMENTS DESCRIPTION 1 00 00 500 Hz tone s01a dac Adjust Notch Freq or s01b dac recorder Pitch to null tone Single tone requires small filter size 2 02 30 400 Hz and 1100 Hz s02a dac Adjust recorder Pitch to tones null tones s02b dac Compare adaptive and notch filters 3 05 30 Swept tones s03 dac Adjust Prediction Span and Adapt Rate comparing effects 06 20 High frequency hiss s04 dac Adjust LPF cutoff and 4 osso 50 Radio interference interference s05 s0s dac e 09 40 A C hum s06 dac Hi Res Ee restores high frequencies Adjust Comb Frequency or recorder pitch to minimize 60 Hz hum 7 11 00 Telephone A C hum s07 dac Adjust Comb Frequency or recorder Pitch to minimize 60 Hz hum 16 30 Jail Cell s09 dac Hi Res Graphic restores high frequencies 9 Reg 20 45 Bar music s11 dac Filter cannot separate voices spoken or sung but does reduce muffling 23 25 Interview and 12 dac argument 25 50 Radio TV 13 dac 2CH adaptive Ref Canceller filtering using a reference Cancellation limited by
122. phones Often the noise frequency will not remain absolutely constant but will vary slightly due to modulation recorder wow and flutter and acoustic beating Therefore you may need to increase the Notch Width from its minimum setting to keep the noise within the notch For maximum noise reduction set the Notch Depth to 60dB It is best to adjust the Notch Depth up from GO dB until the tone is observed then increase the depth 5 dB CGAY Page 65 Eg Notch Frequency r Notch Depth 4066 Hz 35 dB 4 4 Notch Width Filter In Figure 4 27 Notch Filter Control Window 59 Hz Description of controls is as follows Notch Frequency Notch Depth Notch Width Filter Button Specifies frequency in Hertz which is to be removed from the input audio Minimum Notch Frequency is 10 Hz while maximum Notch Frequency depends upon the System Bandwidth setting Notch Frequency is adjustable in 1 Hz steps Depth of the notch that is generated Notch Depth is adjustable from 10 dB to 60 dB in 1 dB steps Width of the generated notch in Hertz NOTE Minimum Notch Width varies with System Bandwidth Configuration and Number DSP Stages Used to switch the Notch filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also availab
123. place the slot right on top of the signal This is best done by adjusting the Slot Frequency up or down 1 Hz at a time while listening to the Slot filter output on the headphones Usually the signal frequency will not remain constant but will vary slightly due to modulation recorder wow and flutter and acoustic beating Therefore you may need to increase the Slot Width from its minimum setting to avoid having the signal move in and out of the slot C4 LX m Slot Frequency Stopband Attenuation 10 Hz 10 dB 4 H k Slot with Filter In Se Figure 4 31 Slot Filter Control Window To optimize background noise reduction for your application set the Stopband Attenuation to 600B If however you wish to leave a small amount of the background noise mixed in with the isolated signal adjust the Stopband Attenuation to the desired value Description of controls is as follows Slot Frequency Specifies frequency in Hertz which is to be enhanced in the input audio Minimum Slot Frequency is 10 Hz while maximum Slot Frequency depends upon the System Bandwidth setting Slot Frequency is adjustable in 1 Hz steps Stopband Specifies amount in dB by which frequencies other than the Slot CA Page 70 Attenuation Slot Width Filter Button Frequency are attenuated Stopband attenuation is adjustable from 10dB to 60dB in 1 GB steps Width of the generated slot in Hertz NOTE Slot Width va
124. ponents present In these situations set the Enhance Harmonics option to either Odd or Even EI LS Fundamental Frequency Harmonic Limit 60 000 Hz 2182 Hz g nm LR Attenuation Enhance Harmonics Hain 60 dB Al C Even Figure 4 26 Inverse Comb Filter Control Window Description of controls is as follows Inverse Comb Frequency Harmonic Limit Attenuation Enhance Specifies fundamental frequency in Hertz of Inverse Comb filter Slots are generated at multiples or harmonics of this frequency NOTE The Inverse Comb Fundamental Frequency changes whenever the System Bandwidth setting is altered if you change the System Bandwidth setting you will need to readjust the Fundamental Frequency for any Inverse Comb Filters selected Specifies frequency in Hertz above which no slots are generated Minimum Harmonic Limit is 100 Hz while maximum Harmonic Limit depends upon the System Bandwidth setting Harmonic Limit is adjustable in 50 Hz steps Depth of attenuation outside the slots Attenuation is adjustable from 10 dB to 60 dB in 1 dB steps Specifies whether slots will be generated at All Odd or Even G Page 64 Harmonics multiples or harmonics of the Fundamental Frequency If for example the Fundamental Frequency is set to 60 000 Hz then selecting All will generate slots at 60 Hz 120 Hz 180 Hz 240 Hz 300 Hz etc Selecting Odd will generate slots at 60 Hz 180 Hz 300 Hz etc
125. press the CLEAR button This will cause all adaptive filter coefficients to be reset to zero allowing them to reconverge anew assuming the ADAPT FREEZE switch is in ADAPT CGAY Page 119 6 MCAP CUSTOMIZATION OPTIONS 6 1 Configuring MCAP for Different COM Ports The MCAP Master Control software is factory configured to communicate with the external processor over RS232 communications port 2 COM2 This is likely to work for most systems However in some cases where a serial mouse is connected to COM2 instead of COM1 or in general when the available COM port is not COM2 it may be necessary to reconfigure the software to operate on a different COM port as follows 1 On the MCAP Master Control menu bar click on the Settings menu bar option When the pulldown menu appears click on Local Connect Settings then ComPort The display will now appear as follows Figure 6 1 Settings wv Connect to MCAP Disconnect from MC Ap Local Connect Settings ComPort gt amp COM1 Remote Connect Settings gt BaudRate gt DSP Settings Use Local MCAP Use Remote MCAP v Enable Panel Input Level Controls Enable Panel Headphone Controls Figure 6 1 ComPort Selection Menu Now click on the desired COM port To attempt connection through this port make sure the Use Local MCAP menu option within the Settings menu is checked and click on Connect to MCAP If any error messages appear then
126. r Source Tape Player E Z CSEE MCAP 0220 O O O heeee s RS292 Enhanced Tape Recorder Headphones Figure 3 1 MCAP Connection Diagram 4 With the MCAP installation procedure in Section 2 2 complete run the MCAP Master Control program by double clicking on the screen icon It may require several seconds for the program to load and initialize the external unit 5 With the MCAP Master Control Panel displayed on your PC screen insert the MCAP Training CD into the Source Audio Player then press the PLAY button 6 Adjust the Input Level slider controls on the MCAP Master Control Panel until the Input Levels bargraphs indicate GREEN with occasional peaks in the YELLOW range Note that some mono segments of the source audio may not have audio recorded on the right channel 7 With the phones VOLUME initially set to MIN place the stereo headphones on your ears and slowly adjust the phones VOLUME for comfortable listening NOTE If you wish to listen to the unprocessed audio going into the MCAP toggle the MONITOR switch on the MCAP external processor to MAIN INPUTS To listen to the MCAP output toggle the MONITOR switch to OUTPUTS Also toggle the SELECT switch to listen to both output signals STEREO left only LEFT or right o
127. recorder such as a CD Mini disk Micro cassette or DAT recording device Always consider that the quality of the playback and recording media will limit the quality of the processed and enhanced audio The recommended device is a DAT recorder with digital inputs because the MCAP can transfer the audio digitally DAT recorders have excellent bandwidth and signal to noise SNR ratio 3 1 Fast Start Fast start the MCAP as follows 1 Connect the LEFT and RIGHT channel line level audio outputs AUDIO OUT jacks of your Source Audio Player to the LEFT PRI and RIGHT REF1 ANALOG MAIN INPUTS BNC jacks on the MCAP external processor rear panel as shown in Figure 3 1 Note that the RIGHT REF1 LREF REF2 and RREF REFS signals are only used in stereo configuration and or with the Ref Canceller Filter in any configuration 2 If you wish to record the enhanced audio connect the line level audio inputs AUDIO IN jacks of your Enhanced Audio Recorder to the LEFT MONOUT and RIGHT MONOUT ANALOG MAIN OUTPUTS BNC jacks on the MCAP external processor rear panel as shown in Figure 3 1 3 Connect your stereo headphones to either of the two PHONES jacks on the MCAP external processor front panel as shown in Figure 3 1 Turn the phones VOLUME control to MIN It is also recommended that headphones be connected to the Enhanced Audio Recorder s headphone jack to confirm that the output signal is being properly recorded G Page 10 Compute
128. ries with System Bandwidth Configuration and Number DSP Stages Used to switch the Slot filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the Slot filter and its controls follows in Figure 4 32 Note that the slot width is defined at its 6 dB points Stopband Attenuation dB Attenuation dB Bag Slot Width Slot Frequency Frequency Hz Figure 4 32 Slot Filter Graphical Description 4 4 12 Multiple Slot Filter Application The Multiple Slot filter is used to isolate or slot up to 16 single frequency signals such as tones or whistles from the input audio eliminating all other audio This is the exact opposite of the Multiple Notch filter function and is accomplished using a frequency sampling synthesized 1024 tap FIR filter which is calculated in the PC by the MCAP Master Control program CGAY Page 71 To properly utilize the Multiple Slot filter you will first need to identify the frequencies of all signals to be isolated this is best done using the Spectrum Analyzer window See Section 4 7 for complete instructions on operating the Spectrum Analyzer window Once the frequencies of the signals have b
129. rmware Update Procedure It is possible that when the software is run a message will appear informing you that the firmware version of the MCAP device itself is not up to date The MCAP software will continue to run but some features may not work correctly To update the firmware us the Firmware Update Wizard that was installed with the rest of the MCAP software You will see an icon like the one below D Firmware Update Wizard Figure 2 3 Firmware Upgrade Wizard Icon Clicking on the icon will start the Wizard which will walk you through updating The top cover of the MCAP will need to be removed so a Phillips head screwdriver is required GN Page 9 3 GETTING STARTED Operation of the MCAP system is highly intuitive most operators can quickly learn while using The Fast Start procedure in Section 3 1 should allow first time users to quickly begin processing tapes and utilizing the basic enhancement capabilities of the MCAP system For a lesson in operating the MCAP controls it is recommended that the user also complete the MCAP Tutorial in Section 3 2 Section 3 3 applies the MCAP to different noise problems contained on the MCAP Training CD In the following sections the Source Audio Player and an Enhanced Audio Recorder will be referred to The Source Audio Player can be any type of playback unit such as a CD Mini Disk Micro cassette or Digital Audio Tape DAT playback unit The Enhanced Audio Recorder can be any type of audio
130. rocessor Rear Panel The rear panel of the MCAP external processor appears as follows Figure 1 4 Figure 1 4 MCAP Rear Panel BNC jacks for line level input and output signal connections are provided Normally the ANALOG MAIN INPUTS are used for signal inputs but if extra REFERENCE signals need to be provided for Ref Canceller operation the REF INPUTS may be used Additionally XLR connectors are provided for AES EBU digital input output A two position slide switch allows selecting between ANALOG or DIGITAL MAIN INPUTS for the LEFT PRI and RIGHT REF1 signals the LREF REF2 and RREF REF 21 inputs are always analog A second three position slide switch allows the user to specify the DIGITAL OUTPUT SAMPLE RATE for recording onto DAT or CD AC power 85 263VAC 47 63Hz is supplied through the AC POWER jack using the supplied IEC line cord If the DC POWER option is purchased with the unit the DC POWER jack can be used to input 9 18 VDC source using the supplied pigtail A 9 pin RS232 jack is provided to connect the MCAP external processor to the CONTROL PC normally used using the supplied cable A second 9 pin RS232 jack and cable allows connecting a second computer to be used as a dedicated spectrum analyzer display optionally used The supplied SPEC DISP utility allows this feature to operate see Section 7 2 INSTALLATION INSTRUCTIONS 2 1 Cautions to User To install the MCAP hardware a
131. rovided The Filter stage to be displayed is specified in the Filter Select block by clicking on the desired Filter The number of coefficients in the Filter to be displayed is specified in the Coefficients to Display block by clicking on the desired number this causes the specified number of coefficients to be horizontally scaled to fit within the display area Regardless of the length of the Filter clicking on All causes all coefficients in that Filter to be displayed Vertical scaling of the Filter s coefficients for display is accomplished by clicking on the desired Scale factor Supported Scale factors range from 1X to 200X A moveable Marker allows Time and Value readout at any point in the Coefficient Display CAY Page 108 0 5 j 0 5 24 833 msec 31 944 msec Marker Filter Select Filter 1 Time 28 389 msec Coef 511 Value 0 3893 DR RE E Ge Filter 2 Filter 3 Coefficients to Display TER 64 128 256 512 AN1024 i HideControls Figure 4 63 Coefficient Display Window Description of controls is as follows Filter Select Block Used to select the DSP Filter stage whose coefficients are to be Coefficients to Display Block Scale Block displayed Available options depend upon the System Bandwidth Configuration and Number DSP Stages settings Used to select how many coefficients in the selected Filter are to be horizontally scaled to fit the display area
132. s useful for removing in band noise from the input signal The Lower Cutoff Frequency is usually set below the frequency range of the noise while the Upper Cutoff Frequency is set above the frequency range of the noise While listening to the filter output audio the Lower and Upper Cutoff Frequencies can be incrementally adjusted to achieve maximum elimination of noise while minimizing loss of voice The amount of volume reduction in the stopband region can further be controlled by adjusting the Stopband Attenuation setting maximum volume reduction is GOOD The slope at which the volume is reduced from normal at each Cutoff Frequency to the minimum volume specified by Stopband Attenuation can also be controlled by adjusting the Transition Slope setting Description of controls is as follows Lower Cutoff Specifies frequency in Hertz below which no signals are attenuated Frequency Frequencies between this cutoff and the Upper Cutoff Frequency are attenuated Minimum Lower Cutoff Frequency is 0 Hz while the CGAY Page 58 Upper Cutoff Frequency Transition Slope Stopband Attenuation maximum Lower Cutoff Frequency is 10 Hz below the Upper Cutoff Frequency Lower Cutoff Frequency can be adjusted in 1 Hz steps NOTE The Lower Cutoff Frequency can never be set higher than 10 Hz below the Upper Cutoff Frequency E LS Lower Cutoff Frequency r Upper Cutoff Frequency Out Hz 10 Hz Filter In 4 gt
133. s the icon for the PASSTHRU program This icon resides in the same folder as the MCAP Control Program Double click on this icon to start the PASSTHRU program Note that PASSTHRU cannot run at the same time as the MCAP Control Program on the remote PC Each program needs exclusive access to the MCAP and cannot share this device at the same time M H Figure 8 2 PASSTHRU Program Icon CAY Page 128 8 3 PASSTHRU Program Main Screen Figure 8 3 shows an example main control screen for the program The MCAP Connection box displays the current serial communication port Com Port and baud rate for the MCAP connection Similarly the MODEM Connection box displays information about the MODEM connection This information may be different for each remote PC since different serial ports and baud rates can be used The Status Icon always displays information about what the program is doing or what the program expects the remote user to do As shown in Figure 8 3 the program is waiting for the user to click on the Auto Answer button before it allows the Base Location to have access to the remote MCAP The program menu bar has two commands Configure and Exit Selecting Configure allows the user to customize the Com Port and baud rate for each connection Configure also allows other customizations as described in the next section Select Exit to close the program Passthru Configure MCAP Connection Com Port Com3 38400 MODEM Connect
134. sed to control each DSP Filter Stage In Mono and Stereo Indep configurations as many as eight Filter boxes will be displayed in Stereo Linked configuration as many as four Filter boxes will be displayed Select the type of filter to be implemented by each stage by using the Select button to pull up the Filter Selection Window See Section 4 3 1 Filter Selection Window Set up the selected filter s parameters by using the Control button to display the control screen for that filter See 4 4 DSP Filter Control Windows Switch each filter stage In or Out of the process using the Filter In Out button Reset and freeze each adaptive filter stage without affecting the other stages using the Clear and Adapt Freeze buttons Used to control each DSP Equalizer stage In Mono and Stereo Linked configurations one Equalizer box will be displayed In Stereo Indep configuration a separate Equalizer box will be displayed for each channel Select the type of equalizer to be implemented by using the Select button to display the Equalizer Selection Window see Section 4 3 2 Equalizer Selection Window Set up the selected equalizer s parameters by using the Control button to display the control screen for that equalizer See Section 4 5 DSP Equalizer Control Windows Switch each equalizer stage In or Out of the process using the Equalizer In Out button Clears the filter coefficients of any adaptive filters selected If no adaptive filters are present t
135. setups without being connected to a PC For a simplified functional block diagram see Figure 1 2 LEFT IN CPRD PGA Limiter FIGHT IN CREF ei PGAS Liniter 25 35 KHZ ANALOG Q EI DIGITAL CONTROL PC AES EBU Input LREF JN REF 2 ei POAS Liniter RREF IN REFS PGA Liniter ge ANALYZER Ge Programmable Digital Processor DIGITAL QUTPUT SAMPLE RATE 9 32 kHz AES EBU Qutput PHONES Figure 1 2 MCAP Functional Block Diagram 1 3 External Processor Front Panel CAS Page 3 The front panel controls are arranged into three logical groups HEADPHONE MONITORING controls STAND ALONE controls and input level controls The MONITOR switch allows the user to listen to either the MAIN INPUTS the REF INPUTS or OUTPUTS signals with a pair of stereo headphones connected to either of the two 1 4 PHONES jacks The SELECT switch allows the user to listen to the signals in STEREO or to focus on either the LEFT or the RIGHT signal Switching the MONITOR or the SELECT switch does not alter the signal flow to the LEFT and RIGHT analog line output BNC connectors The VOLUME can be adjusted to a comfortable listening level The STAND ALONE controls allow the user to select and run one of four previously programmed filter setups stored in internal nonvolatile memory The OPERATION switch must be set to STAND ALONE for these special controls to become opera
136. space such as HELLO THERE the password at the Base Location must have the same sequence of characters If the base uses two spaces between the words HELLO THERE the passwords will not match even though they look very similar to the eye View Edit Password Password g9675309 JENNY 6 to 25 characters Figure 8 6 Set Entry Password Screen Clicking on About in the Configure Drop Down Menu will pop up a screen displaying the version number and copyright information for the PASSTHRU program 8 4 Program Operation This section describes the steps necessary to connect the Base Location PC to the Remote MCAP CAY Page 131 8 4 1 Base Location One Time Initialization Only 6 Turn off power to the base PC and MODEM Connect the MODEM to the base PC with a serial cable Connect the MODEM to the phone line Turn on power to the PC and MODEM Double click the MCAP Master Control icon to start the MCAP Master Control program From the pull down menu click on Settings then RemoteConnectSettings Verify the com port and baud rate for the MODEM change if necessary 7 Click on Settings then RemoteConnectSettings then Phone Number Password Verify that the telephone number and password of the remote location are set properly 8 Click on File then Exit to store these settings in a disk file and exit the program 8 4 2 Remote Location One Ti
137. splay Buttons Pressing the Spectrum Analyzer button at any time brings up the Spectrum Analyzer window For fast access to the Spectrum Analyzer window press lt Alt S gt on the keyboard See Section 4 7 for complete instructions on operating the controls in the Spectrum Analyzer window Pressing the Coefficient Display button at any time brings up the Coefficient Display window For Fast access to the Coefficient Display press lt Alt E gt on the keyboard See Section 4 8 for complete instruction on operating the controls in the Coefficient Display window 4 6 2 Display Select Window Clicking on View in the menu bar causes the following menu Figure 4 61 to appear Coefficient Display Spectrum Analyzer v Displays Off Figure 4 61 Display Select Window Click the mouse on the desired type of display Only one display will operate at a time The display currently active is checked in the View menu Currently the only supported displays are the Spectrum Analyzer and the filter Coefficient Display Select No Display to turn off any display currently operating For fast access to the Display Select window press lt Alt V gt on the keyboard CAS Page 103 See Section 4 7 for complete instructions on operating the controls in the Spectrum Analyzer window For complete instructions on operating the Coefficient Display window see Section 4 8 4 7 Spectrum Analyzer Window Application To properly utilize the DSP Filter and Equali
138. t channels When Independent the AGC gains are not necessarily equal each increased in response to only its own output channel For most applications the AGC outputs should be Linked to avoid annoying Left Right differential gain shifts however Independent AGC gains should be used when processing two unrelated monophonic signals in a Stereo configuration 4 2 5 On Screen Headphone Control On Screen control of the Headphone monitoring system is accomplished by clicking on the Headphones button in the Output Levels box to bring up the Headphone Control Window shown in Figure 4 9 CAY Page 41 Left Amplifier Right Amplifier Pri In Post Delay Refi In Post Delay Listen To Nee Both Odb C Left Only F 0 C Right Only Balance Tener IT Enable Panel Controls Figure 4 9 Headphone Control Window The Left Amplifier and Right Amplifier Combo controls allow the user to individually specify any signal in the enhancement setup for listening on the left and right headphone outputs These controls work similarly to the Yellow and Blue Trace Signal Select controls on the Spectrum Analyzer screen except that there is an additional capability to monitor the MCAP input signals before or after the input Path Delay line Pre Delay or Post Delay The Listen To option buttons allow the user to listen to Both signals in stereo the Left Only or the Right Only Volume and Balance controls allow tailoring of both ears
139. t entry box by entering the value in its text entry box or by clicking on the Limit Threshold line using the mouse pointer and adjusting it to the desired value e The Attack Time can be adjusted through a range of 1 to 250 milliseconds by using the scroll buttons beside its text entry box or by entering the value in its text entry box e The Release Time can be adjusted through a range of 50 to 2000 milliseconds by using the scroll buttons beside its text entry box or by entering the value in its text entry box Other indicators are the Input and Output Level Displays The Input Level Display shows the current envelope level for the stage The Output Level Display shows the output level of the stage calculated by multiplying the input envelope by the gain The current position on the LCE graph is shown via a dancing orange dot The Current Gain display shows the current instantaneous gain value of between 90dB and 90dB as calculated by the MCAP CAY Page 98 4 5 DSP Equalizer Control Windows This section provides detailed description of the control window for each equalizer type For any digital Equalizer block the control window for the selected equalizer is accessed by clicking on the Control button The output equalizer is used to make final adjustments to the noise reduced digitally filtered signal In the process of enhancement high frequencies might be boosted and signal level can be reduced This is common in 1CH adap
140. tch Freq uency of each notch to be used to the desired noise frequency Usually the noise frequencies will not remain constant but will vary slightly due to modulation wow and flutter and acoustic beating Therefore you may need to increase the Notch Width of each notch from its minimum setting to avoid having the noise move in and out of the notch Once all the Notch Freqs and Notch Widths have been entered you will need to build the actual filter using the Build command Unlike the Notch Filter which responds to controls immediately the Multiple Notch Filter must be constructed in CGAY Page 67 the computer and transferred to the external unit A brief delay thus occurs before the filter is implemented Figure 4 29 depicts the control window for notches 1 through 8 A second window for 9 through 16 can be button accessed by clicking on the Control 9 16 button E x Notcht Freq width Notch2 Freq width Notch3 Freq width Notch4 Freq width 1575 Hz 3859 Hz 5400 Hz Out Hz Build 4 gt 4 gt 4 gt 4 gt 264 Hz 53 Hz 53 Hz 53 Hz 4 gt 4 D 4 D 4 r Destroy Notchd Freq width Notch6 Freq width Notch Freq width Notch8 Freq width Control 9 16 Out Hz Out Hz Out Hz Out Hz 4 gt 4 L 4 4 L Elter In 53 Hz 53 Hz 53 Hz 53 Hz H b 4 L 4 L 4 L Figure 4 29 Multiple Notch Filter Control Window Description of controls is as follows
141. ter Freq controls are adjusted The Boost Cut controls work similarly to the Center Freq and Width controls as the Boost Cut can be typed directly or selected with the slider control The Boost Cut adjustment ranges from 60dB to 16dB in 1dB increments Warning Pay particular attention to the Output Level and Stage Overload indicators when positive Boost Cut values are used as the maximum digital signal range of the MCAP can easily be exceeded The Substage In Out buttons allow the user to quickly bypass Substage Out any stage The Input Atten slider control is normally set to OdB but can be used to insert an attenuation of as much as 60dB in 1dB increments This is a useful method for quickly reducing the overall gain of the four combined parametric stages G Page 94 without having to manually adjust all four Boost Cut controls for example when a Stage Overload occurs allowing the overall shaping characteristics of the parametric filter to be retained Use the 0 button to quickly restore the input attenuation to OdB The Output Level bargraph which indicates the actual parametric filter output signal level is provided for convenience It functions identically to the signal bargraphs on the MCAP Master Control Panel The Master In Out button allows the entire parametric filter to be clicked In or Out of the process at any time A graphical description of a parametric filter and its controls follows in Figure 4 56 Width
142. th minimum signal loss Make All 0dB This button instantly moves the slider controls for all bands to OaB Button defeating the entire equalizer This is a useful feature when it is desired to reset all sliders from scratch All Down 1dB This button shifts all sliders down by 1dB from their current position Button no slider however will be allowed to go below 40dB This button allows the user to shift the entire equalizer curve down so that there will be room to move one or more sliders up relative to the others Store Button This button allows the user to store a slider configuration to any of 60 disk memories 10 for each of the 6 System Bandwidth settings CAS Page 100 which will not be lost when the computer is turned off Clicking this button brings up the window shown in Figure 3 12 of Chapter 3 0 Clicking one of the 10 jukebox style buttons will cause the current slider configuration to be stored in that disk memory for the current System Bandwidth Clicking the Cancel button exits the Store window without storing the slider configuration in any of the memories Recall Button This button allows the user to recall a previously stored slider configuration from one of 11 disk memories for the currently selected System Bandwidth Clicking this button brings up the window given in Figure 3 13 of Chapter 3 0 Clicking one of the 10 jukebox style buttons will cause the sliders to be configured to the previously stored se
143. the filter s effectiveness therefore the Num Averages should be set large At least 32 averages are recommended but more will give a smoother spectrum from which to build a filter The Analyzer Gain should be increased to display weaker energy components Do not overload OVL the analyzer as the spectral information would become corrupted CAY Page 82 7 Ea Analyzer Filter Operation EQ Range Gain iTe eaic Run Ka Range 50 dB Build Equalize Voice 7 5 Num Averages C Attack Noise Gain 25 dB Filter In 64 S 4 gt Store Lower Voice Limit Upper Voice Limit r Output Shape 281 Hz 3164 Hz Flat Voice Recall EE 111 a gt Pink ox Figure 4 42 SIF with EQ Range set to 50dB Try to capture a representative spectrum using the Freeze Run button Once a stable representative spectrum is obtained on the display Freeze the analyzer This same spectrum may be used for several different variations of the filter changing Limits or Range as an example NOTE Immediately following Freeze the screen will continue to update briefly as the PC is receiving the final frozen spectral data from the external unit Limits In Equalize Voice operation the Upper and Lower Voice Limits should bracket the voice signal Outside these limits the audio is bandpass filtered Setting the Lower Limit above 300 Hz and the Upper Limit below 3000 Hz may adversely affect intelligibility Try
144. the phone line for ringing The program will answer and automatically connect any authorized base location to the remote MCAP Exit Program f After the Base Location has hung up and broken the link wait for PASSTHRU to detect the disconnection and change the action button label on the Main Screen to Abort Click on the Abort button Wait for PASSTHRU to change the action button label on the Main Screen to Auto Answer Click on Exit on the menu bar to exit the program CGAY Page 133 8 4 4 Base Location Normal Operation Each Session Start Program 1 Verify the MODEM is connected to the base PC 2 Verify the MODEM is connected to the phone line 3 Turn on power to the PC and MODEM 4 Start Windows and double click on the MCAP Master Control icon to start the program 5 Click on Settings then Connect to Remote MCAP to dial up the remote location and establish connection The MCAP Master Control program is now connected to the remote MCAP The base operator may operate the MCAP as desired Exit Program 1 Click on File then Exit on the menu bar to exit the program 8 4 5 In Case Of Trouble Problem After click on the Auto Answer button PASSTHRU never displays the message Waiting for remote user to call Suggestion PASSTHRU CANNOT RUN AT THE SAME TIME AS THE MCAP CONTROL PROGRAM EXIT THE MCAP CONTROL PROGRAM The MODEM must be compatible with the Hayes AT Command Set Re
145. tional For complete instructions on using the STAND ALONE memories see Sections 4 9 4 and 5 0 The OPERATION switch selects whether the unit is to be operated by the MCAP Master Control program via RS232 interface to a PC PC CONTROL setting or in a stand alone configuration without a PC STAND ALONE setting For complete instructions on using the STAND ALONE feature see Sections 4 9 3 and 5 0 Note H the OPERATION switch is moved from STAND ALONE to PC CONTROL while the MCAP master control program is operating the RS232 interface must be reinitialized Do so by clicking on the Settings in the menu bar and then on Connect to Local MCAP The POWER switch must be switched to the ON position in order for the unit to operate The front panel of the MCAP external processor appears as follows Figure 1 3 DIGITAL AUDIO CORPORATIO a ZF OPERATION power STAND ALONE N ONIT O Figure 1 3 MCAP Front Panel The input level controls allow the user to adjust the input signals to the proper level for STAND ALONE processing screen controls can be used when operating with a PC Tricolor LEDs are provided to indicate signal levels when the LEDs are GREEN the signals are at the proper levels while YELLOW indicates caution RED indicates input overload Input signal levels are also indicated by the displayed bargraphs on the MCAP Master Control Panel See Section 4 G Page 4 1 4 External P
146. tive filters The output equalizer enables the operator to restore naturalness to the speech and de emphasize residual high frequency hiss Alternatively a Limiter Compressor Expander can be used to achieve a good output signal level 4 5 1 20 Band Graphic Equalizer Application The 20 band Graphic Equalizer is an easy to use linear phase FIR digital filter that is used to reshape the spectrum of the final output signal Reshaping is accomplished with twenty vertical scroll bars also called slider controls which adjust the attenuation of each frequency band These controls are very similar to the slider controls found on analog graphic equalizers common to many consumer stereo systems and thus should be very familiar to even the novice user However unlike analog graphic equalizers this digital equalizer has some very powerful additional capabilities For example the Normalize button allows the user to instantly move all slider controls up until the top slider is at OdB The Make All OdB button instantly sets all the sliders to OdB The All Down 1dB button instantly moves all sliders Down 1dB None of these functions is available in an analog graphic equalizer Notice also that the 20 sliders are spread across the selected Bandwidth and that the frequency spacing is optimized for voice processing Additionally since a computer with a disk drive operates the equalizer a Store and Recall capability is available This allows the user to s
147. tore commonly used slider configurations in disk memories so that they can be instantly recalled later whenever they are needed without having to manually adjust the slider controls CGAY Page 99 ain S 10 6 6 4 2 2 6 6 6 6 6 6 4 A BZ 10 14 18 dB a a a a a a a a a a a a a a a a a a a a Mess d Make All 0dB All Down 1dB Store Recall Equalizer In X e e e e X X e e e e e e kd e e X X X Freq 100 300 500 700 300 1 1K 1 3K 1 5K 1 7K 1 9K 2 2K 2 7K 3 2K 3 8K 4 4K 5 0K 5 6K 6 2K 6 8K 7 4K Co _ Figure 4 58 20 Band Graphic Equalizer Control Window Description of controls indicators is as follows Slider controls The twenty vertical scroll bar slider controls are used to set the frequency response of the equalizer Each slider can set the gain of its frequency band to any value between OdB and 40 dB in 1dB steps Center Frequency Note that the Center Frequency of each band is labelled underneath each slider and that bands are more closely spaced at low frequencies Gain Indication Above each slider control the gain for that frequency band is given The gain can also be visualized graphically by the position of the slider control Normalize Button This button instantly shifts all slider controls up together until the top slider is at OdB After normalization the relative positioning of the sliders remains the same This allows the digital equalizer to implement the desired equalization curve wi
148. tric filter without altering the overall shaping function An bargraph Output Level indicator as well as an independent Internal Overload indicator assists the user in avoiding output distortion by preventing the dynamic range limits of the filter substages from being exceeded CGAY Page 93 Input Atten Substage 1 Wide Substage 2 Mid Gubstage 3 Wide Output Level Odg Center Freq Center Freq Center Freq e 853 Hz 2297 Hz 2574 Hz 3 4 Sa gt 4 d 4 d o 3 Width Width Width n 0 426 50 Hz 890 31 Hz 858 00 Hz ns 4 l gt 4 d 4 d 18 24 Boost Cut Boost Cut Boost Cut a Lan dB DA dB EL dB on 4 D H D H D 42 GE Sen SIRRA Suggestion Adjust each substage separately with all other substages clicked out Figure 4 55 Tri Parametric Filter Description of operation The Center Freq text box slider controls allow the user to either type in the desired Center Frequency of each stage directly or to make manual adjustments Click on the left right arrow button at either end of the slider to make fine adjustments to center frequency or drag the scroll box to make coarse adjustments Center Frequency can be specified in 1 Hz steps The Width text box slider controls work similarly to the Center Freq controls The displayed Width however is proportional to the Center Frequency and will thus be automatically changed whenever the Cen
149. trol Panel features are shown in Figure 4 1 CAY Page 31 From this screen all external processor capabilities can be accessed The Master Control Panel is organized logically from left to right with audio input controls at the far left digital signal processing controls in the middle and audio output controls at the far right Master Control functions are as follows Menu Bar Input Levels Box System Bandwidth Box Configuration Box Used to access the Master Control pulldown menus which allow storage and recall of filter setups from disk files configuring RS232 communication with the external processor viewing signal spectra and filter coefficients storage of filter setups in nonvolatile memories inside the external processor for Stand Alone operation generation of hardcopy setup reports and getting online help See Section 4 9 Master Control Pulldown for further details on these features Used to view input signal levels via bargraph display adjust input levels via slider controls if desired setup Input HPFs and switch them In and Out of the process setup input Limiters and switch them In and Out of the process and to setup the Path Delay lines See Section 4 2 Input and Output Processors for further details on the Input HPFs Limiters and Path Delay lines Used to select the bandwidth of the audio processor which most closely matches that of the input signals physically adjusts the sampling rate of the MCAP
150. ttings for that memory Clicking the eleventh button labelled Previous will cause the sliders to be restored to the settings they had prior to the last memory recall at the current System Bandwidth setting Successive clicks of Recall then Previous perform A B comparison of two equalizer configurations 4 5 2 Spectral Graphic Equalizer Application For many output equalization requirements the 20 Band Graphic Equalizer described in Section 4 5 1 should be adequate Its resolution is limited having only 20 coarsely spaced slider controls some applications require finer control of the output spectrum shape For this reason the 115 band Spectral Graphic Equalizer is provided a 460 band version is also available as the Hi Res Graphic Filter described in Section 4 4 14 The Spectral Graphic Equalizer is essentially a 115 band graphic equalizer but does not have 115 separate slider controls Rather it allows the user to precisely draw the desired equalizer shape on the computer screen using the mouse with as much or as little detail as desired Once the equalizer shape has been drawn a linear phase digital filter is created and loaded into the digital equalizer stage of the MCAP for implementation The Edit feature allows the user to make adjustments to the equalizer shape while the Normalize button allows the user to shift the entire equalizer curve up until the highest point is at OO CGAY Page 101 A Store and Recall capabil
151. urrently selected signal and allows the user to scroll through the available signals and select a different one with a mouse click CAY Page 106 Marker Section Spectrum Display Hide Controls The Gain scroll bar allows the user to apply digital gain to the Blue Trace input signal prior to FFT analysis allowing signals which fall below the 70dB dynamic range of the analyzer to be viewed Gain may be adjusted from OdB no gain to 40dB This Gain setting does not affect the audio only the Spectrum display If the Gain setting is too large the Blue Trace input may be overloaded causing a distorted spectrum display When an overload does occur the Gain label will change to OVL and the blue magnitude readout at the bottom of the display will change from blue to red Used to move the vertical red marker in the Spectrum Display area described below allowing frequency Freq and magnitude Mag readout of any point in the spectra The horizontal scroll bar is used to precisely place the marker at the desired point in the spectra Make coarse adjustments to marker position by dragging the scroll box slider with the mouse Click on the scroll bar or scroll arrows at either end of the scroll bar to make fine adjustments Clicking the Find Peak button instantly moves the marker to the largest magnitude in the Spectrum Display For faster placement of the marker click the mouse cursor on the desired point in the Spectrum Disp
152. us Figure 3 13 Tutorial Recall 20 Band Graphic Equalizer Window Try adjusting the Num Averages slider control Note that as the Num Averages parameter is increased the spectrum traces react more slowly and smoothly to the input signal Return the Num Averages setting to 8 Click on the Run Freeze button until Freeze is indicated You should see the spectrum waveform stop updating Click on the Clear button in the Averager block both spectrum waveforms should now be cleared completely away Restore the Run Freeze button to the Run indication to allow the spectrum waveform to resume responding to the input signal Click the mouse anywhere on the spectral waveforms to move the vertical red marker to that point A readout of frequency Fre and magnitude Mag of the Yellow and Blue traces will be indicated below the display grid Use the horizontal scroll bar in the Marker block for more precise marker control Click the Find Peak button to automatically move the marker to the largest magnitude displayed Adjust the Gain controls for both the Yellow and Blue traces and note how the indicated magnitude for each trace is increased as gain is increased The spectral analysis freezes immediately however the display will briefly continue to update as remaining data is read from the MCAP external processor G Page 23 48 49 50 10 20 30 50 40 60 70 0 Freq 9 Hz Mag 8086 Hz MaE D E l Both S Mo
153. w allows the user to adjust the Release Time Maximum Gain and Link settings of the AGC Release Time specifies how quickly the AGC will react to decreases in output signal level The shorter the Release Time the more quickly the AGC will react The Release Time options are 50 milliseconds fastest 100 milliseconds 200 milliseconds and 400 milliseconds slowest For most voice applications the 200 milliseconds setting is recommended Release Time settings less than 200 milliseconds may result in annoying pumping sounds as the AGC changes gain during rapid fire conversations Maximum Gain specifies how much gain the AGC can apply in its attempt to bring the output signal up to the proper level The greater the Maximum Gain the lower the output signal level that can be brought up to proper level The Maximum Gain options are 5dB 10dB 15dB 20dB 25dB 30dB and 35dB For most near party far pary applications the 10dB setting is recommended Maximum Gain settings greater than 10dB may elevate background noise during pauses in speech A soft AGC using 5aB is often useful even when large voice level differences are not present The Link option is provided in Stereo configurations to give the user the option of making the two output channels Linked or Independent In Mono configuration outputs are always Linked When Linked the AGC gains are equal at all times and are increased in response to the largest signal level of the two outpu
154. ways have different values this is because the frequency width of an octave is proportional to Cutoff Frequency Specifies amount in dB by which frequencies below the Lower Cutoff Frequency and above the Upper Cutoff Frequency are ultimately attenuated Stopband Attenuation is adjustable from 10dB to 60dB in 1 dB steps Used to switch the Bandpass filter in and out of the process without affecting the other filters in the process Button indicates Filter In when the filter is in the process or Filter Out when the filter is out of the process NOTE The Filter button is also available in the Filter block for each filter on the Master Control Panel A graphical description of the Bandpass filter and its controls follows in Figure 4 21 CGAY Page 57 Attenuation dB Lower Transition Slope dB Octave lt Upper Transition Slope L dB Octave Stopband A Lower Upper ttenuation Eat beach CBee SEN Upper Stopband dB Band Band Lower per Cutoff off Frequency Frequency Frequency Hz Figure 4 21 Bandpass Filter Graphical Description 4 4 6 Bandstop Filter Application The Bandstop filter is used to decrease the energy level lower the volume of all signal frequencies above a specified Lower Cutoff Frequency and below a specified Upper Cutoff Frequency The signal region between the Lower Cutoff Frequency and the Upper Cutoff Frequency is called the stopband region The Bandstop filter i
155. y the Notch Harmonics option will be set to All causing frequencies at all multiples of the Comb Frequency within the Notch Limit to be reduced However C Page 60 certain types of noises have only the odd or even harmonic components present In these situations set the Notch Harmonics option to either Odd or Even EJ Comb Frequency Notch Limit 88 670 Hz 1440 Hz a H Notch Depth Notch Harmonics Filter In 20 dB All C Even Figure 4 24 Comb Filter Control Window Description of controls is as follows Comb Frequency Notch Limit Notch Depth Notch Harmonics Filter Button Specifies fundamental frequency in Hertz of comb filter Notches are generated at multiples or harmonics of this frequency NOTE Comb Frequency changes whenever the System Bandwidth setting is altered if you change the System Bandwidth setting you will need to readjust the Comb Frequency for any Comb Filters selected Specifies frequency in Hertz above which no notches are generated Minimum Notch Limit is 100 Hz while maximum Notch Limit depends upon the System Bandwidth setting Notch Limit is adjustable in 50 Hz steps Depth of notches that are generated Notch Depth is adjustable from 10 dB to 60 GB in 1 dB steps Specifies whether notches will be generated at All Odd or Even multiples or harmonics of the Comb Frequency If for example the Comb Frequency is s
156. y in Hertz below which all signals are attenuated Frequency Frequencies between this cutoff and the Upper Cutoff Frequency are unaffected Minimum Lower Cutoff Frequency is 0 Hz while the maximum Lower Cutoff Frequency is 10 Hz below the Upper Cutoff Frequency Lower Cutoff Frequency can be adjusted in 1 Hz steps NOTE The Lower Cutoff Frequency can never be set higher than 10 Hz below the Upper Cutoff Frequency CA Page 56 Upper Cutoff Frequency Transition Slope Stopband Attenuation Filter Button Specifies frequency in Hertz above which all signals are attenuated Frequencies between this cutoff and the Lower Cutoff Frequency are unaffected Minimum Upper Cutoff Frequency is 10 Hz above the Lower Cutoff Frequency while the maximum Upper Cutoff Frequency depends upon the System Bandwidth setting Upper Cutoff Frequency can be adjusted in 1 Hz steps NOTE The Upper Cutoff Frequency can never be set lower than 10 Hz above the Lower Cutoff Frequency Specifies slope at which frequencies below the Lower Cutoff Frequency and above the Upper Cutoff Frequency are attenuated in dB per octave Sharpest attenuation occurs when Transition Slope is set to maximum while gentlest attenuation occurs when Transition Slope is set to minimum Note that the indicated value changes depending upon Cutoff Frequency System Bandwidth Configuration and Number DSP Stages settings Also note that the Lower and Upper Transition Slopes al
157. zer stages it is often necessary to measure the frequency characteristics of the input signal This assists in determining the type of filtering needed Also after processing the signal it may be desirable to compare the frequency characteristics of each digital filter output to those of the input signal thus determining the effectiveness of each digital filter A dual channel FFT spectrum analyzer with selectable inputs is ideal for accomplishing these tasks The dual channel FFT spectrum analyzer is used to view the frequency spectrum of the signal at any stage of the enhancement process Two traces a Yellow Trace and a Blue Trace can be displayed either simultaneously or separately Either trace can be configured to display any signal The Averager is used to average successive spectra to achieve a slower smoother display Each trace consists of 920 spectral lines with a useable dynamic range of 70dB Adjustable Gain controls allow up to 40dB of digital gain to be applied to each trace to boost low level signals to better fit within this dynamic range An overall dynamic range of 110 dB is thus available A moveable Marker allows frequency and magnitude readout at any point in the two spectra The Find Peak feature allows the marker to be moved instantly to the largest magnitude displayed CGAY Page 104 Freq 9 Hz Mag 8086 Hz vier DIR e ES E 2 Primary In ES Display a Line Output z Both 64 Mode Num Averages we

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