A -Scan - GAMPT mbH
Contents
1. ultrasound Comupter Tomographie ol xj File Options Signal view 00 00 29 Speed eis C Move Sis Wa E 100 4 gt ula a are AScan B mode TM mode CT 1 MHz Sound Velocity m s 1500 0 4 framerate 15Hz Scan Length 8 Angle 1 Accuracy mm Be oe lA Taw deta _ Stat CT Scan FFT Fitter Stop Haf Time Depth HF Amp HF AMP grayscale color i Input Voltage V Transmission mag 1 unfiltered Attenuation 10 08 all 0 50 100 150 200 t DeTime ps 0 50 100 150 200 Gain Dutput Cursor Curso Diference Amplitude sain T 35 dB 30dB 19915 799ps 600ps 0 9 12 08 09 Amp ATOF 4 D 10 20 30 40 50 60 70 80 Position in mm 18 Software Four images are displayed The upper two show attenuation and time of flight unfiltered On the lower two a mathematical filter function was used to increase the contours In dependance of the basic image an increase of image quality can be reached By comparison of attenuation and time image additional information about the ob ject can be received Through choice all four or only one image can be displayed A mouse click on above the images direct to the colour scaling explained in B mode All four images or the maximised image can be changed If the measure is finished the images can be saved by the menu item File gt Save Images or the whole form can printed with File gt P2. Scan can be connected via parallel port interface LPT as well as via USB port The respective choice can be given in the program form Data Transfer You will find under the menu Options the item Data Transfer data transfer A xi data transfer q F data transfer gt transfer to 45 can transfer to 45 can transfer to AScan USB 1002 Device not found OK data connection checked switched to simulation PE connection PE connection C Simulation LPT i USB C Simulation LPT e USB serial 66451000 no adapter info found GAMPT AScan Version 1 0 0 0 OK data connection checked PE connectio C Simulation f LPT C USB parallel port numbe te LPT 1 E _ UP 2 M check CT Scanner transfer to CT Scanner e check CT Scanner OK connection checked serial GACT 1000 GAMPT CT Adapter 1 0 0 0 check CT Scanner refresh connection The program will check the connection and when it is successful the result will be given in green letters When there is no connection the software shows an error message in red letters with the probable reason In this case the program will switch automatically to the simulation mode In simulation mode the data will be generated in the computer this mode also works without a A Scan it can also be used for demonstration The program will stay in simulation mode until the next successful data transfer check gt The program saves the actua
3. At evaluations with the mouse pointer there can be little differences Both in TM Mode and B Mode on y axis of the image the time of flight is shown If you switch to depth scale in the down scaled main screen display this will also change the scale in image For correct image display the cor rect sound velocity of the sounded material has to be chosen gt When there was a scanner connected and recognized from the program see chapter Data Transfer the B Mode scan can also be done with it In this case it is not necessary to convert time to local coordinates this will be done by the scanner for scanner control see chapter Computer Tomography The TGC can be very helpful to emphasize strong attenuated signals from deeper areas But with wrong adjusted TGC there can also be a image falsification For this the image above can serve as example The acrylic block has a height of 80 mm depth because measured from above All signals from deeper depth behind the ground echo are multiple echoes emphasized by TGC 15 Software 3 5 3 Computer Tomography 3 5 3 1 Basics gt Surely this chapter is interesting also for users which have no scanner However the here described meas urements can be done only with a scanner and the corresponding control unit gt In the offline simulation mode the program works also without a connected scanner system The following illustration should demonstrate the difference between a stan
4. position is shown as red value deactivating or hiding the signal view in the down scaled main screen save computer calculation time it can be helpful for older or slower computer see menu SignalView gt In simulation mode the values for Path Length Angle and Accuracy are overwritten by the program and not selectable by the user 3 5 3 3 Operation Measurement A measurement is always started in the middle of the object Are the values for Scan Length Angle and Accu racy adjusted and the measure was started with Start CT Scan the program demands to move the scanner to the middle of the object When this not happened until now in the Move mode the user can do it by using the switches and knobs at the scanner control unit After this the scanner is moving by in position and starts the first scan The respective alteration of amplitude and time of flight in comparision with the first measure point are shown in the diagram right below The actual position is shown as vertical line At the same time the position angle and duration of measure are displayed as values in the upper screen part With the buttons jf a measure can be interrupted stops the measure When a scan for an angle was finished the measured data will be converted to gray scale values or rainbow color and respectively to the angle included into the images on left side This will repeat after each angle so the image generation can be observed step by step
5. the data In this case the data will be written into the tmp path show negative values directory While the program is running it works with these data With a in AScar window use ALT or ALT lt restart of the program the initial data will be overwritten with the original values stored by an administrator in the installation path The tmp path value take affect only when the user has no write access to the installation path The time shift executes a displacement of the shown data on x axis That can be more comfortable for some ab solute time measurements 1 e to compensate a time delay line For each know transducer frequency a time shift value can be edited gt For exact measurements we recommend always to measure relative by using both cursors gt That is why the time shift is deactivated by default Input Voltage Y Reflection 1 0 100 time shift 4 45 ps Time us Is the time shift nevertheless activated it will be shown in the main screen under the diagram as red coloured value The starting point of the diagram line is displaced by the given value in the picture above 4 45 us With help of the keys ALT arrows right left the time shift for the actual frequency can be changed without the pa rameter window Caution not possible for all overloaded windows 10 Software 3 3 2 Data Transfer The program has to know where the data come from For this we have to adjust the data transfer The AM
6. 66 11 44 06 With the button the measure is started The button display change to Stop the measure is running until this button is pressed gt All other buttons are inactive during the measurement The duration of the measure is documented as measurement time in the upper area During a measure the actual measured A scan line is converted to gray scaled values and in the left diagram shown as vertical bar The y axis represent the time of flight or depth the x axis is a measure for the measurement time In the Time Motion pic ture the last time section is shown the picture above shows the last 6 sec of the measure When the measure is finished the picture can be evaluated Moving the mouse over the picture shows the actual x y coordinates above the diagram The width of the time section can be changed with the arrows under the pic ture With help of the input fields Zoom Area it is possible to zoom the picture in y direction In the area color scale the appearance of the picture can be changed It is possible to change from gray scale to rainbow coloured dis play the contrast can be changed with the moving bar or with the input fields level width The value pixelwidth affects the with of each vertical scan line in the image Smaller pixelwidth values go to a better x resolution but t needs more calculation time A meaningful value can be estimated with the frame rate value shown in the right AScan window during the measure
7. AMP AScan B mode TM mode CT Input Voltage Y Reflection a a ree 100 e Time ps TSC dB 35 30 4 25 20 0 20 40 60 80 100 Gain Dutput Dilemas Amplitude GAMPT mbH 35 dB 30 dB 19 9 ps 80 0 ps 60 1 ps 0 8324 11 38 26 Further software options are switching range area automatic mode advertisement transmission reflection switch between time of flight and measurements depth in dependence of sound velocity zoom functions data export print frequency and cepstrum analysis FFT of selectable signal area frequency filter Time Motion mode manual guided B mode imaging optional computer tomography and scanner guided B mode After starting the program the measure mode is active and the main screen AScan mode is open Beginning from here all actions and evaluations can be selected and started Software 3 2 Main Screen AScan Mode The main screen is shown in the picture below In the upper screen part the A scan signal the frequency of the connected transducer the mode reflection transmission and the actual position of the cursors red and green line are displayed The cursors can be positioned by mouse move the mouse to the cursor the mouse pointer will change or by keyboard arrow keys left right cursorl up down cursor2 O x File Options Scale view Modi About 1 MHz Sound Velocity m s 15000 4 gt FFT Fiter Stop Hat Time Depth HF Amp HF A
8. EDUCATION MPT SAM Scan User Manual Gesellschaft fur Angewandte Medizinische Physik und Technik mbH GAMPT mbH Hallesche StraBe 99F Fon 49 0 3461 278 691 0 06217 Merseburg g a MP T Fax 49 0 3461 278 691 101 a os Sy ampPT www gampt de General Safety Instructions Before the operation of the A Scan and the ultrasonic probes read the following instructions carefully to your own as well as to the operational safety of the device gt Pay attention that the device can only be powered by an AC electrical outlet 100 250 volts 50 60 Hertz The opening slits in the device serve for ventilation and should be kept absolutely free to avoid an overheat ing of the device Never try to input objects into the vents of the device because it can cause short circuits or electric shocks Control the ultrasonic probes before every application Exchange damaged probes Never use probes that show cracks Remove the ultrasonic probes from the device by pulling at the plug Never pull at the cable The same ap plies to all other cables connected to the device To connect to socket Probe use only sensors delivered from company GAMPT mbH Attention At the socket can be voltage peaks up to 300V The A Scan is a lab device not a medical product Do not use the ultrasonic probes at persons or other creatures Pay attention to the special operation and safety instructions in the corresponding chapte
9. MP AScan B mode TM mode cT Input Voltage Y Reflection 10 0 50 100 150 Depth mm 35 dB 30 dB 14 9 mm 100 2 mm 85 2 mm 0 9314 11 39 42 The scale of x axis can be changed from time scale time of flight measure to depth scale Buttons or alternative menu Scale For the depth scale calculation the sound velocity is needed This value is to be edited in the respective input field default 1500 m s for water The Up Down button pair left beside the dia gram serves for the amplitude resolution upper pair and moving the zero line bottom pair The permanent refreshing of the A scan line can be interrupted by the button freeze and continued with Start With the buttons the measurement range maximal time of flight or depth can be switched between 100 us or 200 us For the display of the measured values in the A scan line it can be selected if only amplitude red only HF data blue or both should be shown The selection is done with the buttons Amp HF or HF Amp alternative menu View In the bottom diagram the Time Gain Control with all parameters start point rise width and threshold is shown Whereas emitting output power and receiving amplifier always impact to all measurement values the TGC effects only a selectable time range The gain works only in this time range Thereby the slope can be changed in position width and rise With it it 1s possible to emphasize especially interest
10. With Move Path Length the sledge will move by the value given in the input field be side the button Rotate Angle works analogously CT Scan With Scan Length determine the width of the measurement field It should be always a value which guarantees that the object is completely in the field With Accuracy the distance between two measurement points is determined The number of points per scan is given by e curacy Angle defines how much the object is turning after each scan The scans will be repeated until 360 is reached or overstepped Start CT Sca starts the measure Sound Field With it a single scan can be measured Starting from the actual position Scan Length will be moved in steps deter mined by Accuracy The alteration of amplitude signal red and time of flight blue are displayed in the diagram With the values can be exported into a text file ACII file By using a hydrophone this mode can be used to measure the sound field of an ul trasonic transducer in lateral or vertical direction Software To get a steady motion of the scanner it does not stop at each measure point When the scanner reaches the next measure point the data will measured on the fly When the speed is to high for the selected accuracy t can be that the scanner reaches the next position before the computer evaluation 1s ready with the last one In this case the values are interpolated and as warning the actual
11. a roo 4 Position 80 0 mm Close 1 MHz Sound Velocity m s 1500 0 4 Scan Lend fag a joj 0 Go femme E afoj statctscan FFT Fiter Stop Haf Time Depth Amp HF HF AMP image i 1 unfiltered Attenuation 2 unfiltered Time of Flight Input Voltage M Transmission 1 00 3 al a g 0 0 50 100 150 200 eo Time ys 3 Shepp and Lagon Filter Attenuation 4 Shepp and Lagon Filter Time of Flight 0 50 100 150 200 Gain Output Amplitude 35d MdB 100us 250us 150us 09300 141423 Ultrasound Comupter Tomographie 4 ql File Preferences Signal View Direction Speed i fq No gt a w fy el feo 4 es E00 4 Save Scan Start Sound Field Scan Amp 7 TOF 759mm 112 3 00 00 04 Position 80 0 mm Move CTScan MSc 1500 0 4 FFT Fiter Stop Haf Time Depth Amp HF HF AMP 1 MHz Sound Velocity m s Input Voltage 4 Transmission 1 00 A AAA A A EA AA A AA ei ee 0 50 100 150 200 Time ps ER ELSE PEN MEET rr loca NE CHAR ER PER ori an AAA a a a A neues anne nase eer 0 50 100 150 200 Amplitude 100us 250us 15048 09304 14 15 20 Gain Dutput 35 dB 30 dB 17 Move With it the sledge of CT scanner can be positioned By pressing the sledge goes into the selected direction un til the button 1s pressed again
12. dB with steps of 5 dB For the TGC start point rise width and threshold are continuously adjustable with a gain up to 30 dB With the BNC outlets different signals can be transferred to an external oscil loscope In materials provided there is also a measure and control software for Microsoft windows see chapter Soft ware With it t is possible to measure differences in amplitude and time of flight Additionally the simultane ous visualizing of the HF and amplitude signals can be done wherewith in contrast to conventional A scan de vices the waveform character of ultrasonic signals can be demonstrated In a next diagram form and progression of the TGC are shown 2 2 Ultrasonic Probes Components The ultrasonic probes distinguish oneself by a high sound in tens ty and short sound pulses With that they are particularly appropriate for pulse echo mode All probes have a robust metal box and are waterproof protected at the sensor surface The probes are delivered on demand with a special plug for connection to the GAMPT Scan or with a BNC plug for uni versal use The blue coded 1 MHz probes are suitable especially for large penetration depth because of their high sound intensity Their employment is recommended particularly for investi gations of strong damping materials and for generation of Rayleigh and shear waves respectively For that the probes can be utilized either as transmitter or as receiver The red c
13. dard X ray CT and the GAMPT ultrasonic CT X ray CT GAMPT US CT Transducer Transducer Receiver Ata X ray CT an emitter radiates through the object the attenuated radiation 1s registered by a receiver behind the object at several points Scan 1 simultaneously Now the transducer receiver eon fF oF fT system turns around the object patient and starts the next scan This will repeated until all needed angles will be reached At our US CT there is only one receiver We can measure the attenuated intensity only at one point That is why for each angle we have to measure the intensity in series at several po sitions The distance of these positions is the accuracy their sum the scan path After such a scan in our system instead of the transducer receiver system the object will be turned and the next scan is started First of all be sure that beside the connection to the APT Scan also the communication with the scanner works right menu item Preferences gt Data Transfer see also chapter Data Transfer gt It is pointed out that it is possible to work with activated TGC at CT measurements but that it can cause unpredictable results The used CT algorithm cannot handle different amplification during a measure It is highly recommended to deactivate the TGC during CT measurements 16 Software 3 5 3 2 Scanner Control The construction of the form is similar to t
14. duction The ultrasound echography also sonography has developed to one of the most important investigation methods among others in medicine and NDT non destructive testing There are unreviewable multitudes of ultrasonic devices for different applications They all work on the same basic principles of emitting a mechanical wave whose reflection will be and recorded in an echogram The A T Scan is a high sensitive ultrasonic measurement system which can be connected to a PC or simple to an oscilloscope With the delivered software an extensive signal analysis can be done HF signals amplitude sig nals B mode M mode spectral analysing The ultrasonic probes will be connected with robust snap n connectors The probe frequency is automatically recognized from the device With help of the adjustable emit ting and receiving power it is possible to fit the ultrasound signal to nearly each arbitrary investigation object Thereby the intensity loss of ultrasonic signals from deeper investigation areas can be corrected by a Time Gain Control TGC Threshold start and endpoint or rise of TGC are free adjustable The most important signals Trigger TGC HF and amplitude signal are available on BNC sockets For the setup of lab experiments there is an extensive choice of ultrasonic probes 1 2 and 4 MHz and accessories Thereby the theme area goes from physically basics of ultrasound up to industrial and medical applications In con
15. e was filtered here this range will not be shown i e in the FFT evaluation This is also valid for the imaging methods B TM and CT mode 13 Software 3 5 Imaging Methods With the AMP Scan not only the one dimensional display of the data in diagrams can be done it is also possible to generate two dimensional images In this chapter 3 imaging methods with the A Scan are presented 3 5 1 Time M otion Mode The picture below shows the Time Motion Mode form On the right sight there is a down scaled main screen Here the respective buttons and functions are also available With the menu item Signal View this display can be deactivated or hidden by deactivating hiding the measure display or decrease shown window size the computer reserve calculation time This can especially for slower computers increase the image quality ioi x Eile Options Signal View Zoom Area Measurement Start fuel o 4 gt fico 4 pes 76 AScan B mode TM mode i CT _ color scale 1 MHz Sound Velocity m s 1500 0 4 gt framerate 15Hz F 3 level ER i m gay C rainbow wan O 4 offs fe T inverted pixelwicth ms 15 A hl per Fiter Stop Full Time Depth HF Amp HF AMP Input Voltage Y Reflection 1 0 Time 20 usidiv Z 100 us F VAN A f Wi N f A 0 20 40 60 80 100 i GAMPT At 1 secidiv I 6 sec Gan Output EF Amplitude bH 5 35 dB 30dB 199us 799us 600ps O8
16. he B Mode and TM Mode On right side there is the down scaled main screen Below there is an additional diagram in which during measure the alteration of amplitude signal red and time of flight blue is shown The choice area left above Move CT Scan and Sound Field serves to select an action respectively to the se lected choice the display will change With Direction and Speed the movement of the scanner can be controlled speed is given in percent whereas 100 is the maximal possible speed Ez ltrasound Comunter Tomograpne E File Preferences Signal View Direction 00 00 04 en Speed Pe Move CTScan C Sound Field a 100 gt fs C Position 80 0 mm Close 4 a 1500 0 4 Es lanoi 100 4 Move Path Length Es 300 4 gt Rotate Angle Move Free wel 1 MHz Sound Velocity m s FFT Fiter Stop Haf Time Depth Amp HF HF AMP pees a 1 unfiltered Attenuation a 2 unfiltered Time of Flight Input Voltage 4 Transmission 1 00 all taf RL 2 0 50 100 150 200 Time ys lt E gt 2 TGC dB 35 3 Shepp and Lagon Filter Attenuation 4 Shepp and Lagon Filter Time of Flight 0 50 100 150 200 Gain Dutput CN 35 dB 30 dB Amplitude 100us 250us 150us 0 9304 14 14 52 ultrasound Comupter Tomographie d a raci G R o x File preferences Signal view 00 00 04 Speed C Move CT Scan C Sound Field
17. ing areas and also to suppress disturbing signals gt Pay attention not to compare quantitative values from TGC amplified range with other ones This is espe cially valid for amplitude measurement Software In the bottom screen area there are some status information Among others there are the time of flight values depth values of the selected cursor positions in yellow the difference between the red and green cursor is shown On left side the adjusted receiving amplification gain and emitting output power are displayed Right there s the amplitude voltage value at the position of the mouse pointer middle of the cross A A A AA A A ee ee eee ee Between the diagrams there 1s a button panel with different arrows These arrow buttons serve the zoom function on the x axis The first two move the axis one division to left and right the next two zoom in and out The dou ble one at least performs an auto scale of the x axis This stays active until another arrow is selected or the meas urement range has been changed The arrows beside the diagram work analogue for y axis To input values into the program there are fields like sound velocity top Sound Velocity m fi 500 0 4 slo Ue NO left The values can be edited directly or varied by using the mouse and the arrow buttons Alternatively 1t can be changed with the keys up down with page up down the increment value increase tenfold When a limit is reached it will be signed by red co
18. ional USB adapter 10 MHz per channel 256 x 257 x 156 mm 100 V 250 V wide range power supply ca 20 VA 1 MHz 2 MHz 4 MHz 65 mm x 27 mm Y control unit via USB max 350mm Imm 1 3 Bibliography Millner R Ultraschalltechnik Grundlagen und Anwendung Physik Verlag 1987 Kuttruff H Physik und Technik des Ultraschalls S Hirzel Verlag Stuttgart 1988 Krautkr mer J Krautkr mer H Werkstoffpr fung mit Ultraschall Springer Verlag 1968 Advanced Sutilov V A Physik des Ultraschalls Akademie Verlag Berlin 1984 Morse P M Ingard K U Theoretical Acoustics McGraw Hill Book Company New York 1968 20 Experiments 6 Experiments In the following there is a list with suggestions for experiments which can be realized with the A Scan and the respective accessories You find a description of the setup and experiment in the experimental manuals ofthe company GAMPT Physical Basics PHYO1 Ultrasonic echography A scan PHYO2 Velocity of ultrasound in solid state material PHY03 Attenuation of ultrasound in solid state material PHY04 Attenuation of ultrasound in liquids PHYO5 Spectral investigations PHY06 Frequency dependence of resolution power PHY07 Shear waves in solid state materials PHY08 Ultrasonic B scan PHY09 Ultrasound computer tomography PHY10 Characteristic of sound field PHY16 Mechanical scan methods PHY20 Determination of the focus zone Industrial Applicat
19. ions INDO Non Destructive Testing NDT INDO2 Rayleigh waves INDO3 Level measurement IND06 Angle beam measurement INDO7 Time of flight diffraction technique TOFD INDO8 Detection of discontinuities Medical Applications MEDOI MEDO2 MED04 Ultrasonic investigation with the eye dummy Ultrasonic TM mode Ultrasonic investigation with the breast dummy 21
20. l data transfer choice so it is not necessary to edit them every time starting the program But doing so it will also remember the simulation mode a notice about that will be given If the choice check CT scanner is activated also the connection to the scanner will be checked The choice should only be activated when there is a scanner gt When an USB adapter is recognized his answerback will be checked and shown Pay attention to use only adapter that are suited to the devices A scanner adapter works only with the scanner and not with the AS can device and reversely When no connection could be established it is recommended to go on step by step especially by using USB adapter o first switch off the devices take off all data cable and adapter o now connect the adapter without device USB adapter should be recognized right now o connect device and switch on refresh connection o when there is a scanner do the same steps with it gt By use of USB adapter it can be that other USB devices are influenced Especially via the AScan adapter a lot of data will be transferred so a great part of the USB bandwidth is used 11 Software 3 4 Frequency Analysis 3 4 1 Fast Fourier Transformation Behind the button there is the fre quency analysis evaluation For this the ES frequency analysis i al x Print Export Cepstrum Close spectrum of the scan line is calculated with help of a F ast F ourier T
21. loured value Then the limit value is valid Software 3 3 Menu Options 3 3 1 Parameter The max frame rate impact how often data are transfered from the echoscope and displayed in the diagrams The here given value is only a max frame tate Hz EN 4 b reference point Keep n mind that data transfer and evaluation need a cer tain time With a to high value the effective frame rate can be lower the DOLS aan program will work as fast as possible Whereas it can be that other mplitude programs are slowed down Cursor Cursors gt The here adjusted value has no impact when a measure was started in Ciertas B TM or CT mode In the imaging measurements the effective frame rate can be higher than before because different queries are not tmp path i es Pe necessary see also pixelwidth in chapter TM mode ES parameter OF x e gampt trap change path In the Colours area the diagram lines or cursors can be adapted A mouse E time shift offset us click to the el beside Colours will reduce the area fr time shift enabled Sn oe ajel tmp pain During the program operation changed values 1 e sound err bo io ve na Lane rate a and a different data will be au Normally th s will be done into the installation path of the program With good reason not eE o oo gt all students have write access to the program directories So they could not Sr 0 00 ll write
22. ment 14 Software 3 5 2 B rightness Mode Display and function of the B mode imaging are s milar to the TM mode LT RE Eile Options Signal View Zoom Area Measurement _ Path Length Start So as tE hsa gt AScan Bmode TMmode CT color scale 1 MHz Sound Velocity m s 2700 0 4 gt framerate 15Hz level ee gay C rainbow ewa o foe inverted pirelwidth ms 15 A Fer Fiter Stop Full Time Depth HF Amp HF AMP Input Yoltage Y Reflection 1 0 A Depth 27 mmidiv Z 135 mm Ax 130 1mm Depth 82 4mm 0 20 40 60 80 100 120 140 Depth mm 0 20 40 60 80 100 120 140 Gain Output Cursor Curso Diference Amplitude PAMP T Ax 50 0 mmidiy I 150 mm 35 dB 30dB 269mm 107 9mm 81 1mm 0 766V 12 06 21 In the picture above the acrylic test block was measured For this the probe was put on the surface and constantly moved from one side of the block to the other The block has a width of 150mm the measure continued 8 3 sec In the B Mode there is a way to assign the measurement time with local coordinates or distances For this acti vate the check mark beside measurement time and edit the path length which was measured Now times on x axis can be converted into distances gt Precondition for this converting from times to distances is that the scan is done with steady speed Also start and stop time has to correspond with the passing way
23. n be performed which can affect the data shown in the upper diagram in main screen E frequency filter band pass filter 7 ic of on neve fos aofo gt MHz gatefom fro gt 5 Eb frequency MHz At first the calculated spectrum is displayed as blue line gt In contrast to the previous frequency analysis all data of the A scan line are used for spectrum calculation and not only these between the cursors A range in spectrum is selectable with help of the moving bar above the diagram The border values of this range are shown as MHz values at the top The filter can now be activated deactivated with the choice offon When the filter is activated all values outside the range are set to zero the red line 1s valid With help of an in verse FFT this filtered spectrum will be back calculated and the result 1s shown in the upper diagram of the main screen With this filter you can eliminate 1 e disturbing signals with high frequencies Such or similar filter system are often used in measurement devices gt To show the frequency filter is activated the button in the main screen is coloured red gt The frequency filter affects the shown measurement signal in the main screen With wrong or senseless pa rameters of the filter no or not analyzable measurement signal might be shown gt The frequency filter works before the other evaluation on the original signal That means when a fre quency rang
24. nection with the scanner system many setups to imaging methods can be build Components 2 1 Control Elements CAM T Scan The A Scan is an ultrasonic A scan device with an outlet for pulse echo operation reflection mode and an additional outlet and toggle switch for operation with two probes in transmission mode The device is available as stand alone version with a parallel interface for data transfer to the PC Optional there is also an USB adapter For better understanding device principles the different components are optically departed A power supply B transmitter C receiver D time gain control TGC E BNC outlets to oscilloscope E D C B A MONITOR TIMER TGC RECEIVER TRANSMITTER POWER 11 gt 71 aegea rec A Trh o 12 boa eet a dB OUTPUT dB gaMPT 13 JLTRASONICO SOLUTIONS RF SIGNAL NES O A SCAN as a ae N ON OFF 109 8 7 654 3 2 A power supply D Time Gain Control TGC 1 on off 7 start point B transmitter 8 slope 2 probe connector transmission 9 width 3 emitting power 10 threshold C receiver E outlets oscilloscope 4 toggle switch reflection transmission 11 signal TGC 5 probe connector reflection mode or receiver 12 signal trigger signal in transmission mode 13 signal ASan HF 6 receiver amplifier 14 signal ASan NF The transmission power is controllable in a range from 0 30 dB in steps of 10 dB For the receiver amplification the range is from 0 35
25. oded 2 MHz probes are suitable for wide range em ployment Because of the higher frequency the axial and lat eral resolution power is evidently better compared to the 1 MHz probes On the other hand the damping of 2 MHz sound in most materials is not yet too large so that investiga tions in middle depth can be obtained easily Especially these probes are suitable for investigations at medical objects and as ultrasonic Doppler probes The green 4 MHz probe is distinguished by an extreme short oscillation decay time which results in the highest axial reso lution power This probe is especially then used when very small structures have to be detected Mainly for investiga tions n liquids the limited penetration depth of some materi als is no problem The high resolution power and therewith related spectral bandwidth recommend this probe particularly for investigations of thin plates Software 3 1 Overview The software AScan serves to record display and evaluate the data supplied from the AM Scan Beside the display of data in diagrams there are different evaluation and filter functions Beside the normal measurement mode the program has an offline simulation mode This simulation will be activated automatically when no de vice 1s connected see also chapter Data Transfer A File Options Scale Yiew Modi About 1 MHz Sound Velocity m s 1500 0 4 gt FFT Fiter Stop Ful Time Depth HF Ame HF
26. ransformation For the spectrum calculation only the val ues between the red and green cursor are used With it you get an information about the occurring frequencies in the measure ment signal Moving the mouse in the new diagram shows the calculated values at mouse position in the right upper corner frequency MHz With the menu item Cepstrum in the FFT window a second diagram will be activated 3 4 2 Cepstrum ES frequency analysis a ioj xj Print Export Cepstrum Close FFT 4 46 y 0 72 cepstrum x 17 62 1 09 ee ee o0 0 08 0 05 0 03 0 20 40 60 80 100 frequency MHz ER distance ps 5 gt a gt a In this second diagram there is once more FFT now with the spectrum data as initial values With it you get in formation if there are specified repeating intervals in the spectrum Such information can be very helpful for evaluation of multiple reflections 1 e at thin plates With the bottom moving bar in the Cepstrum diagram a band pass filter can be adjusted This one will calculate a back transformation from the Cepstrum to the FFT diagram and will be shown as red line 1 e to smooth the FFT The menu Print send the form to a printer with Export either the FFT or the cepstrum data will be written to an ASCII text file 12 Software 3 4 3 Frequency Filter When select the button in the main screen a new window will be open With this a frequency band pass filter ca
27. rint Form Recommended parameters for the GAMPT CT Phantom frequency 1 MHz path length 80 mm accuracy 500 um angle lt 15 3 5 3 4 CT Data Export Beside the button Start CT Scan there is the choice raw data When this is activated during the next measure the AAmp und ATOF data see diagram right down will be stored These data serve as basic for image calcu lation with the CT algorithm When after a measure the images will be saved with menu File gt Save Images then also the raw data of the measure will be saved into ASCH files using similar names like the images In the ASCII files each row corre spond to a CT scan line in first column the angle followed by the AAmp or ATOF data for the different posi tions 19 Technical Details 4 Technical Details AScan Frequency range Measuring mode Transmitted signal Transmitter power Gain TGC Connections Computer port Sampling rate Dimensions Main voltage Power consumption Ultrasound Transducer Frequencies Dimensions CT Scanner Computer port Scan path Lateral accuracy Angle accuracy 1 MHz to 5 MHz switchable between pulse echo and transmission modes Dirac pulse lt lus 10 V 300 V 0 30 dB in 10 dB steps 0 35 dB in 5 dB steps continuously adjustable threshold rise time and duration up to 30 dB gain TGC signal trigger NF signal HF signal all via BNC sockets Sub D 25 socket for LPT opt
28. rs marked with arrowhead and cursive written All rights are reserved by the GAMPT mbH No part of this manual may be copied reproduced translated or transmitted in any form without permission of the GAMPT mbH The GAMPT mbH does not assume responsibility for damages as a result of false use as well as repair and changes which are carried out from third not authorized by the GAMPT mbH Technical and software changes reserved Errors and omissions excepted Copyright 2013 GAMPT mbH Hallesche Strasse 99F 06217 Merseburg Fon 034601 278 691 0 Fax 03461 278 691 101 info gampt de e www gampt de 1 Introduction sc sacceacocolecdesscuasscccesaatsasaeavacecolesdossauesescevast sasweaeaeenocess 4 2 O AN 5 2 1 Control Elements CAMS enana 5 DD O en ne anne see 6 3 SOLA FBSTER RE TEEROUEEERRRONT EU ROESSTERTRE TERROR AHORN EURUFSSTERRRTERRUENEEAREONTEURAESSTERR TR TURRUTON 7 UI A SI OA E Arie Teoh EN Un Tone Mr RENNEN 7 2 Wan sereno Asc Mod ee ns een nen 8 3 3 MN O PAS as 10 ale is ETE EEE A AN 10 3302 DA dd a le ano 11 3 4 EQU AMY cda 12 34 1 Fast eat A 12 342 A A E EAA A 12 343 Fregueney E O 13 3 3 AMA GUO A e edo ed 14 33 41 merito MO dE T 14 39 2 ES dl 15 393 3 Computer Lomo A A iS 16 Seo Basen E ee 16 e e A SO A rl a e 17 3 3 3 3 Operation Mei 18 Sots CEDUTE PO O TE 19 4 Technical DEANS eaen Eaei 20 5 Bibi oeraphy 322020 E 20 6 EXDeriments ia dni acia 21 Components 1 Intro
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