PicoDAC User`s Manual
Contents
1. Figure 3 Figure 4 Figure 5 Figure 6 LIST OF FIGURES PICODAG ee 5 Basic Enhancement Setup 7 PicoDAC Rear Panel Thumb Screws oooooooocccccccnccccnnnnnonnncnnnnnnnnnnnnannnnninnnnnnnns 13 PICODAC Rear Panel Remi tt ti 14 PicoDAC Top Cover Removal ige kennen 14 PicoDAC Battery REMOVAL ts a aan 15 1 0 OVERVIEW 1 1 Introduction The PicoDAC digital filter is a compact low power digital filter intended for dedicated field signal processing applications This powerful signal processor is fully self contained and features e Easy set up and operation Operation with live voice signals tape recorders all types video cassette recorder telephone radio receiver and body transmitter Low power 8 16 VDC operation or internal 9V battery operation Compact enclosure 1 1 H x 2 8 W x 7 2 D Bandwidths of 3 4 5 0 and 7 5 kHz suitable for voice enhancement Ten selectable filters to cover most voice enhancement scenarios Two stages of 256th order fixed and or adaptive filters 1 2 Standard Filter Configurations The ten standard filter configurations in the PicoDAC are optimized for noise removal and Clarification of live and recorded voice signals The standard filter configurations consist of combinations of three different adaptive filter sizes at three bandwidths followed by either another short adaptive filter or a bandlimiting filter The selected combinations of filter bandwidths and sizes allow the operator to easily2. PicoDAC PORTABLE AUTOMATIC VOICE FILTER Model PDAC256 USER S MANUAL CN DIGITAL AUDIO CORPORATION A DRI COMPANY Technology to Make Listening Easier PicoDAC PORTABLE AUTOMATIC VOICE FILTER User s Manual March 4 2004 Document Number 960812 CAY DIGITAL AUDIO CORPORATION A DRI Company 4018 Patriot Drive One Park Center Suite 300 Durham NC 27703 Phone 877 5DACAUDIO Fax 877 5DACFAX sales dacaudio com www dacaudio com Copyright 2004 by Digital Recorders Inc All rights reserved TABLE OF CONTENTS MeO OM ERR VIEW a 3 TA a A O 3 1 2 Standard Filter Configurations ccccccccccccccccccnnnnnnnnncnnnononnnonnnonononnnnnnnnnnnnnnnnnnnnns 3 1 3 Custom Filter Re e Uer NEE 3 e al E E o ee ab 5 2 1 Controls and EIDEN 5 2 2 Typical Setups and Operating Instruchons 6 3 0 STANDARD FILTER CONEIGURATIONS nn 9 3 1 P eprogrammed Filter Setups ren BREI 9 3 2 Hints For Using The PicoDAC Adaptive Filter 10 4 0 CALIBRATION AND SERVICE nt ta 13 4 1 Battery Replacement e 13 SO PICODAC SPECIFIGATION S ee 17 Analog des toi Poo ties toto tot toto tt tt tt tt tio totes ole 17 O A A EEE 17 A O 17 LIST OF TABLES Table 1 Standard Filter Configuration 2 4 44 44 4448440440000 000 400000 9 Table 2 Filter Bandwidihs EE 10 Table 3 Filter Size and Noise Types 2 ccccecceeeeeeeeeeeeeeeeeeeeeeeeeeeeteneeeeedeeeeeeeteeeeneeenee 11 Figure 1 Figure 2
3. Removal To insert the new batteries simply reverse the previous action First insert the terminal end of the battery by slowly prying it between the clips Next press down on the body of the battery It should snap into place Ensure that it is making good contact with the connection terminals Replace the top cover of the PicoDAC by sliding it back into place Re tighten the thumb screws and the PicoDAC is again ready to use For applications where longer battery life is needed longer life lithium batteries are available at many electronics stores 15 16 5 1 Analog Line Input Line Output Phones Output Analog Conversion Level Indication 5 2 Digital Microprocessor Program ROM Filter Coefficient Registers 5 3 Construction Enclosure Size Power 5 0 PICODAC SPECIFICATIONS 0 25 to 5 0 Vrms panel adjustable Zin 50 KQ Rear panel phono connector 1 Vims Zout 100 Q Rear panel phono connector Suitable for stereo headset Front panel volume control and 3 5 mm stereo phones jack 16 bit sigma delta A D and D A Selectable 9 0 12 0 and 18 0 kHz sample rates 3 4 5 0 and 7 5 kHz bandwidth Front panel tricolor LED red 3 dB orange 9 dB green 15 dB TMS320F206 at 20 MIPS Dual DSP56200 Digital Filter Processor 32k x 16 Non Volatile Flash Memory Non Volatile Flash Memory Input switch register 8 bits Output LED register 3 bits Extruded aluminum with a
4. coDAC simply bandlimits any audio applied to the INPUT connector and sends it to the OUTPUT connector bypassing the audio filters The ten standard filter configurations consist of three different adaptive filter sizes small medium and large at three bandwidths 3 4 5 0 and 7 5 kHz followed by either another small adaptive filter or bandlimiting filter bandpass or highpass The selected combinations of filter bandwidths and sizes allow the operator to easily customize the PicoDAC to a wide range of noise removal situations as explained in the following section 3 2 Hints For Using The PicoDAC Adaptive Filter e First it is vital that the source material is prepared as carefully as possible No amount of filtering will enable the operator to hear a voice that is not there For example if the source audio is from a tape recorder and the microphone is beside a loud air conditioner and the target voices are 40 feet away it is doubtful any recoverable voice was recorded on the tape While this sounds like an unusual example it does happen occasionally Also if a tape player is used make sure the heads are clean e Next select the appropriate bandwidth The best results for adaptive filtering are achieved by matching the bandwidth of the PicoDAC to the bandwidth of the recorded voice Table 2 below can help select the best bandwidth For example if the input source is a telephone line that typically has a bandwidth of 3 4 kHz
5. customize the PicoDAC to a wide range of noise removal situations Any of the ten filters can be rapidly selected with a front panel FILTER switch as detailed in Section 3 0 1 3 Custom Filter Configurations Custom filter selections are also available for special applications Please contact Digital Audio Company for further information 2 0 OPERATION The PicoDAC is easy to setup and operate The following section discusses the connections and controls for the unit Following that the remaining sections describe typical setups and how to select the best filter 2 1 Controls and Connectors 2 8 LEVEL POWER P N 8 FILTER R 2 nf eoW P k26 a KA 4 ADO ZQ0e e Y 0 10 0 10 0 INPUT PicoDAC VOLUME PHONES FRONT PANEL D D 0 j ds s AS 10 0 10 o INPUT PicoDAC VOLUME PHONES PicoDAC GND NPUT OUTPUT Enz ON MOS Se Y E Y P AY YF O R WE OFF S N PDAC256 POWER DIGITAL AUDIO COMPANY MADE IN USA RFAR PANFL Figure 1 PicoDAC Refer to Figure 1 for an illustration of the front panel controls e The front panel INPUT rotary control adjusts the gain of the input signal Immediately above this control is a tricolor Level LED that indicates input signal strength Adjust the INPUT control so that the tricolor Level LED flashes green or occasionally yellow Do not allow the input level to
6. e wiring guide for the plug is silk screened on the rear panel The PicoDAC is activated with the ON OFF switch If no connection is made to the POWER connector the PicoDAC is powered from two internal 9 V alkaline batteries NOTE The AC power adapter does not charge the internal batteries The RESET switch is used to restart the adaptive filters by pushing and releasing it This function is particularly useful if the filter crashed and produces only noise in its output a rare event when using the standard filters supplied with the PicoDAC Another example of when to press the RESET switch is when the audio scene changes suddenly requiring a new filter solution this may occur when processing tape recorded conversations that occurred at different locations The RESET switch does not clear the filter type and size settings nor affect the use of the FILTER selector switch but it instead clears the filter coefficients its effect is comparable to turning the power off and then back on The thumb screws are used to remove the PicoDAC top panel to access the batteries refer to Section 4 1 Battery Replacement for more information 2 2 Typical Setups and Operating Instructions Voice enhancement scenarios can take many forms A basic enhancement setup is shown in Figure 2 For the basic enhancement setup connect the original source audio to the INPUT connector on the rear panel of the PicoDAC Notice in this example a tape player is used as t
7. everal different filter configurations may provide similar results See the Section 3 1 for advice on selecting between the various voice enhancement configurations Once the optimum filter configuration has been selected rewind the original source tape player to the beginning of the tape put the tape recorder connected to the PicoDAC OUTPUT connector into Record mode press Play on the original source tape player and create an enhanced version of the original source 3 0 STANDARD FILTER CONFIGURATIONS 3 1 Preprogrammed Filter Setups The filters in the standard PicoDAC are optimized for noise cancellation to increase voice intelligibility Simple noises are generally greatly attenuated However more complex noises such as those from bars or automobiles can only be modestly attenuated The table below shows the characteristics of the filter selected by the front panel FILTER selector switch FILTER Bandwidth Adaptive Filter Size Stage 1 Filter Type Stage 2 Switch Noise Type Setting a a ee A Medium Normal Setting High Pass 300 Hz Large Complex Noises Adaptive Small l Small Simple Tones High Pass 300 Hz 5 0 i 7 5 7 5 on Medium Normal Setting High Pass 300 Hz i Large Complex Noises Table 1 Standard Filter Configuration The FILTER switch setting determines the signal bandwidth and type of filtering based upon the configuration programmed into the PicoDAC When in the BYP mode the Pi
8. go into the red level or distortion may occur e The FILTER rotary switch allows the selection of the desired filter by rotating the small arrow on the switch towards the desired filter number The PicoDAC will automatically reset and load the filter whenever the FILTER setting is changed The headphones can be plugged into the PHONES connector Adjust the audio level with the VOLUME control beside the connector The two position Process Bypass switch selects the state of the filter stages To have the PicoDAC process filter the input signal flip the switch to PRO Process To have the PicoDAC bypass the two filter stages flip the switch to BYP Bypass The red Power LED indicates that the PicoDAC is operating Now refer to the Figure 1 illustration of the rear panel for the remaining controls The INPUT RCA jack is the PicoDAC s input This line level input allows the audio source to be input into the PicoDAC for filtering If the PicoDAC is not powered the INPUT signal is automatically routed to the OUTPUT jack The OUTPUT RCA jack is the PicoDAC s filtered output This line level signal can be connected to a copying tape recorder or loud speaker amplifier if desired If the PicoDAC is not powered the INPUT signal is automatically routed to the OUTPUT jack The POWER connector mates to a 2 5 mm barrel plug To power the unit connect the barrel plug of the AC to 12 VDC power adapter supplied with the unit to the POWER connector Th
9. he original source However the signal could come from many different 6 types of sources such as a live microphone cassette or micro cassette recorder DAT recorder video cassette recorder telephone radio receiver or body transmitter Connect a pair of stereo headphones to the front panel PHONES connector and a tape recorder to the rear panel OUTPUT connector to record the enhanced output It is very important to note that the tape in the original source tape player is not altered in any way by the PicoDAC Figure 2 Basic Enhancement Setup Now that the PicoDAC is connected properly it is time to set the correct input levels for playback Rotate both front panel knobs fully counter clockwise and turn the PicoDAC on Switch the front panel PRO BYP switch to BYP so the signal input will flow directly to the output without being altered Now play the original source from the tape player and adjust the front panel INPUT knob clockwise until the tricolor LEVEL LED flashes green If this LED flashes in the red color region then the knob has been turned too far reduce the INPUT knob setting Adjust the PHONES knob to a comfortable listening level Once the levels are set properly it is time to begin the voice enhancement process Rotate the FILTER switch to a medium filter configuration position e g switch position 3 Listen to the processed output It may be necessary to change the selected filter configuration for best results also s
10. itch positions must be set to OFF If service is needed please contact Digital Audio Company for assistance 4 1 Battery Replacement The normal running time for the PicoDAC on battery power is approximately 6 hours To replace the 9V batteries 1 First disconnect all cables from the unit including the DC power cable Ensure that the rear power switch is in the OFF position Loosen using a flathead screwdriver and remove the thumb screws use a screwdriver if necessary on the rear panel Be careful not to damage any of the components in the PicoDAC by static electricity Before opening the unit be sure to touch a grounded metal object _ w PieoDAC ono INPUT OUTPUT Esav on q er A PO S N POACIS8 POWER Sis DIGITAL AUDIO COMPANY MADE IN USA Figure 3 PicoDAC Rear Panel Thumb Screws 13 2 Remove the rear panel and bezel KS A I y y o K Ki y Ny Y e May er 4 Y Ya Figure 4 PicoDAC Rear Panel Removal 3 While holding the base of the unit gently pull the black top cover toward the rear of the unit Figure 5 PicoDAC Top Cover Removal 14 4 To remove the batteries push firmly on the back the end opposite the terminals of each battery in the direction of the terminals while prying upward The battery should snap out of it s clips back end first gare E al usin N Figure 6 PicoDAC Battery
11. luminum front and rear panels 1 14 H x 2 75 W x 7 2 D overall 8 16 VDC at 400 mA Cable and connector 2 1 mm barrel supplied AC power adaptor supplied Two internal 9V batteries for portable operation 17
12. use filters O and 1 Since the telephone line does not have any voice energy above 3 4 kHz setting the PicoDAC for a higher bandwidth may elevate hiss noise above 3 kHz in the output audio This added noise can make understanding the voice more difficult Typical Equipment Bandwidth kHz FILTER Settings Microcassette Recorder Body Transmitter 2 3 4 5 Standard Cassette Nagra Recorder 6 7 8 9 Table 2 Filter Bandwidths e Lastly listen to the unfiltered input and select the appropriate filter size While selecting too large a filter will reduce simple noises the remaining voice can become sterile or unnatural sounding On the other hand selecting too small a filter size may have less effect on complex noises Select the initial filter size by referring to the table below but feel free to experiment with the other filters and listen for the best results 10 Filter Noise Type Examples Size Small Simple Background music tones 2 6 Noises Medium Normal Background music tones room 0 3 7 Setting reverberations May provide superior quality Large Complex Raspy hum or buzz 1 4 5 8 9 Noises Table 3 Filter Size and Noise Types 11 12 4 0 CALIBRATION AND SERVICE The PicoDAC is designed to make periodic calibration unnecessary However the two internal 9V batteries will periodically need changing If for any reason the top cover is removed the internal DIP switch settings must not be altered All sw
Download Pdf Manuals
Related Search