PicoDAC Configuration Software User`s Manual
Contents
1. Figure 2 3 Bandwidth Selection Radio Buttons 2 5 Programming the PicoDAC The COM Port menu option allows you to select the COM Port that the software will first search for the PicoDAC when programming the PicoDAC If you are unsure which COM Port your PicoDAC is connected to then leave the default option of COM 1 An example of a computers COM Port connections is shown in Figure 2 4 Figure 2 4 A Typical Computer s Serial Ports Make sure to follow the correct instructions detailed in Section 5 0 Transfer Cable Attachment to connect the PicoDAC Transfer Cable For more information about the PicoDAC itself refer to the User s Manual The Program PicoDAC button on the toolbar starts the process of searching for a PicoDAC via the serial ports and transferring the filter settings to the PicoDAC This function can also be selected through the File option in the Menu Bar After the Program PicoDAC button is pressed you will see a window appear that asks you if you are prepared to program all 10 filters This is to remind you that you only need to program the PicoDAC one time once you have all the filters set up the way you want them Next the following window will appear lel Es Finding PicoDAC Port COM 1 Figure 2 5 PicoDAC Transfer Window Finding PicoDAC Several messages will appear in the transfer window informing you that the software is using the Auto COM Port detection feature to find the PicoDAC and then program2. Stage 1 Bandwidth Com C 3 4kHz o Control SCH C 7 5kHz Stage 2 AE C NoAGC ich Adaptive e 1008 AGC Control C 20d8 AGC C 30dB AGC To program the PicoDAC once all the filters have been updated click on the Program PicoDAC button on the toolbar or the Program PicoDAC option in the File Menu CAY a Company Figure 2 1 PicoDAC Control Panel At the top of the PicoDAC Control Panel is a Menu Bar From the File menu item you can choose to create a New filter set Open a filter configuration file Save a filter file As a different or similar file name Program the PicoDAC select a COM Port or Exit the software From the Help menu item you can view the Contents of this help file Search for Help On a topic in this help file or read information About the PicoDAC software Below the Menu Baris the Toolbar Each small icon allows a quick shortcut to some of the Menu Bar items Each icon represents the menu function of New Open Save As and Program the PicoDAC respectively The New menu option allows you to reset each filter to a Pass Thru Filter at 5 0 kHz bandwidth with no AGC This is a quick and easy way to configure a fresh filter configuration 2 2 Customizing Filter Sets The PicoDAC Control Panel allows each of the ten filters to be configured Each filter can be selected by clicking on the tab labeled with its number Each tab corresponds to the number displayed on the rotary switch on the PicoDAC s fro
3. This button instantly shifts all slider controls up together until the top slider is at 0dB After normalization the relative positioning of the sliders remains the same This allows the digital equalizer to implement the desired equalization curve with minimum signal loss This button instantly moves the slider controls for all bands to 0dB defeating the entire equalizer This is a useful feature when it is desired to reset all sliders from scratch This button shifts all sliders down by 1dB from their current position 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 10 0 SPECTRAL GRAPHIC EQUALIZER 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 reshapes the audio to a normal spectral shape might be desirable The Spectral Graphic Equalizer is essentially a 115 band graphic equalizer however instead of having 115 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 det
4. 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 30 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 Attenuation Frequency are attenuated Stopband attenuation is adjustable from 10dB to 60dB in 1 dB steps Slot Width Width of the generated slot in Hertz NOTE Slot Width varies with the System Bandwidth setting A graphical description of the Slot filter and its controls follows in the figure below Note that the slot width is defined at its 6 dB points Figure A 8 2 Slot Filter Graphical Description 9 0 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 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 N
5. 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 filter and its controls follows in the figure below Figure A 6 2 Comb Filter Graphical Description 7 0 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 a Spectrum Analyze 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 headphones Often
6. 9 Normalized Spectral Graphic Equalizer nnnnnnennnnnesereereeenenrrnrnnneeenn 56 Figure A 11 1 Open Imported Coefficient File Dialog BOX rrrrrrrvrrrrrrrrrrrrrrrrrrrrrnnnnnnn 57 Figure A 12 1 Pass Thru Filter Selection 2 22 61 1 0 OVERVIEW 1 1 Introduction The PicoDAC Configuration Software allows for complete setup and control of the ten different filters on the PicoDAC each consisting of two stages The software provides an easy to use intuitive interface for configuring the filter settings and transferring them to the PicoDAC The easy installation of the PicoDAC Configuration software provides Choice of two 256 tap stages within each filter 12 different filter types to choose from within each stage Bandwidth selection for each filter of 3 4 kHz 5 0 kHz and 7 5 kHz Selectable Automatic Gain Control for each filter Filter set 10 filters can be saved for later use Auto COM Port detection for filter transfer to the PicoDAC Each filter can select from one of three bandwidth settings of 3 4 kHz 5 0 kHz or 7 5 KHz as well as the four different Automatic Gain Control AGC settings of no AGC 10 dB of gain 20 dB of gain and 30 dB of gain The two stages within each filter can be independently selected from one of the following filter types One Channel Adaptive Filter Lowpass Filter Highpass Filter Bandpass Filter Bandstop Filter Comb Filter Notch Filter Slo
7. Stage 1 of any filter Set the System Bandwidth to 5 kHz and AGC setting to No AGC 2 Click on the Control button for Stage 1 to bring up the Spectral Graphic Equalizer control window When used for the first time the control window will be the that of the previous figure 3 Click on the New button to draw a new filter The screen will now appear as follows EJ Figure A 10 2 New Spectral Graphic Equalizer Display Had you accidentally clicked the New button you could click on Abort to restore the previous filter You should now notice that all the buttons on the control window have been replaced by a simple Abort button Clicking on Abort at any time prior to completing the curve draw restores the previous filter 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 click button is held down 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 When the mouse click button is released a line segment will be drawn from the last defined point on the curve to the current mouse cursor position For this example placing points at precise frequencies and attenuations is not required draw the curve approximately as shown in the figure below using mouse clicks No
8. x 24 14 provides fastest adaptation Prediction Span Adapt Mode Processor Output 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 64 samples 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 Auto Used to select the output of the filter The normal setting is residue as this is the processed audio The Predict output is the audio subtracted from the original source For example if a ICH Adaptive Filter was being used to remove a tone the Processor Output choice of Predict would output only the subtracted tone 2 0 LOWPASS FILTER Application The Lowpass filter is used to decrease the energy level lower the volume of al
9. 2 Bandstop Filter Graphical Description NY 6 0 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 Fundamental Notch 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 Normally the Notch Harmonics option will be set to All causing frequencies at all multiples of the Fundamental Notch Frequency within the Notch Limit to be reduced However 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 Fundamental Notch Frequency Notch Limit 60 00 Hz 2500 Hz El L_ I Notch Depth Notch Harmonics 30 dB All C Even H C Odd Cancel Figure A 6 1 Comb Filter Control Window Description of controls is as follows Fundamental Specifies fundamental frequency in Hertz of comb filter Notch Notches are generated at multiples or harmonics of this Frequency frequency NOT
10. 5E 002 E 003 E 001 E 001 E 001 E 001 E 003 269745E 002 050633E 002 298883E 003 286449E 002 956892E 002 256326E 003 074622E 002 991908E 002 196839E 003 407519E 002 430844E 002 120655E 003 978514E 002 060535E 002 028165E 003 674714E 002 957611E 003 919611E 003 444848E 002 957981E 003 795490E 003 262311E 002 387280E 003 12 0 PASS THRU FILTER Application The Pass Thru Filter is used to pass the audio through the PicoDAC unaffected except by the bandwidth limitations of the sampling frequency It is often used in conjunction with other filters when only one stage is a PicoDAC filter is needed An easy way to bandlimit the audio to one of the PicoDACs bandwidth settings is to configure both stages in a filter to be Pass Thru Filters The AGC can be used in conjunction with the Pass Thru filters for automatic level adjustment Stage 2 Pass Thru Filter v ein Figure A 12 1 Pass Thru Filter Selection There are no control options for a Pass Thru filter and the Control button is deactivated when the Pass Thru filter is selected for a stage
11. Application 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 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 a Spectrum Analyzer 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 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 E Ei Slot Frequency Stopband Attenuation 1000 Hz 30 dB pi WW 8 Slot Width yo fy eed Figure A 8 1 Slot Filter Control Window To optimize background noise reduction for your application set the Stopband Attenuation to 60dB If however you wish to leave a small amount of the background noise mixed in with the isolated signal adjust the Stopband
12. C ttt A TER eee 45 8 0 SWOT FILTER dd di dd id id da tardas 47 9 0 20 BAND GRAPHIC EQUALIZER use ee 49 10 0 SPECTRAL GRAPHIC EQUALIZER oc cad 51 11 0 IMPORTED COEFFEGIENT FILE zer als 57 11 1 GoefficientFile ForMatd coat arras 12 0 PASS THRU FILTER LIST OF FIGURES Figure 2 1 PicoDAC Control Panel nn nennen 11 Figure 2 2 AGC Radio Butt ns E 13 Figure 2 3 Bandwidth Selection Radio Buttons 13 Figure 2 4 A Typical Computers Serial Portes 13 Figure 2 5 PicoDAC Transfer Window Finding Pica 14 Figure 2 6 PicoDAC Transfer Window Programming PDcoDA 14 Figure 3 1 Save As Setup File Window occcccccccccccccncconcnnncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnonnnn 17 Figure 4 1 Recall Setup File VWumdow nen nnnnnnnnnnnnnnnnnnnn nn 19 Figure 5 1 PicoDAC Rear Panel Thumb Screws nennen nennen nen 21 Figure 5 2 PicoDAC Rear Panel Removal unsurrsuursnen nenn nenn nnnn nenn nenn H nennen nn nn nn nn 21 Figure 5 3 PicoDAC Top Cover Removal nen nn nenn nennen 22 Figure 5 4 Transfer Cable Serial Connector ssssssrrrrrrrrrrrrrrrrrrrrttrtrrrrtrrtrtnrnnnnnne 22 Figure 5 5 Transfer Cable IDC Connector z 4 4444444HHH HH HH HH HH HH HH HH HH HH HH HH rn nn en Hrn nn 23 Figure 5 6 PicoDAC IDC Header iii nl 23 Figure 5 7 Attaching IDC Connector to bcoA nenn nenn nennen 23 Figure 5 8 A Properly Connected Transfer Cable nn nennen 24 Figure A 1 1 ICH Adaptive Filter Control VWumdow nn
13. E 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 Notch Limit Specifies frequency in Hertz above which no notches are generated Minimum Notch Limit is 2 and 1 2 times the Fundamental Notch Frequency while maximum Notch Limit depends upon the System Bandwidth setting Notch Limit is adjustable in 1 Hz steps Notch Depth Depth of notches that are generated Notch Depth is adjustable from 12 dB to 60 dB in 1 dB steps Notch Harmonics 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 set 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 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 barely heard then increase it 100 Hz Adjust the Notch Depth up following
14. PicoDAC PORTABLE AUTOMATIC VOICE FILTER CONFIGURATION SOFTWARE USER S MANUAL GC DIGITAL AUDIO CORPORATION PicoDAC PORTABLE AUTOMATIC VOICE FILTER CONFIGURATION SOFTWARE User s Manual February 6 2000 AD DIGITAL AuDIO CORPORATION A DRI Company 5121 Holly Ridge Drive Raleigh NC 27612 Phone 877 5DACAUDIO Fax 877 5DACFAX sales dacaudio com www dacaudio com Copyright 2000 by Digital Recorders Inc All rights reserved TABLE OF CONTENTS TO OVERVIEW ee 9 EN Tu tee lee EE 9 1 2 AE A SI aoa bak 10 2 0 PICODAC CONFIGURATION CONTROL nttccoccccccncccnonnnnnnnnnnnnnnnnonannnnnnnnnnnnnncnnnnnnnes 11 2 1 PicGODAC Control Pankreas AA AAA RARE DA AAA DA ATRAE AAA AAA 11 2 2 Customizing Filter SS A i 12 2 3 Automatic Gain Control Radio Buttons 12 2 4 Bandwidth Radio Buttons 13 2 5 Programming the PicoDAC er ua a a la 13 3 0 STORING FILTER CONFIGURATIONS rc areas era 17 JJ Save File Dialog Br ar 25er Deren 17 4 0 RECALLING FILTER CONFIGURATIONS dooccccccccccccccccnnnnnnnccnnnnncnnnnnnnnnnncnnnnncnnnnnnns 19 4 Open File Dialog BOX zer en nennt eR A A A 19 5 0 TRANSFER GABLE ATTACHMENT EE 21 5 1 Connecting the Transfer Cable to the PiCODAC rrrrvrrrrvrrrrrrrrrrrrrrrrrrrrrrrrrrrrnnnnn 21 1 0 ONE CHANNEL ADAPTIVE FILTER 2 2 22 27 2 WEOWPASSPIELTER 222222 tenes lah ee 29 3 OHIGHPASS EE 31 2 0 BANDPASS PIETER ota een ee 33 5 O BANDSTOP FILTER EE 37 8 CONE IE LER ude 41 PEO INO T
15. TE The Lower Cutoff Frequency can never be set higher than 100 Hz below the Upper Cutoff Frequency 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 100 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 100 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 12dB to 60dB in 1 dB steps A graphical description of the Bandstop filter and its controls follows in the figure below Figure A 5
16. ail as desired Once the filter shape has been drawn a linear phase digital filter is constructed in the PC and transferred to the external PCAP 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 OdB dit 7 Normalize E re Cancel OK 1020 Hz Atten Figure A 10 1 Spectral Graphic Equalizer 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 grid is provided to assist the user in visually judging frequency and attenuation at any point in the display Freq and Atten Used to precisely readout the frequency in Hertz and attenuation in Readouts dB at any point in the 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 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 PicoDAC Filter Configuration Tabs select the Spectral Graphic Equalizer for
17. ass filter and its controls is shown below Figure A 3 2 Highpass Filter Graphical Description 4 0 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 The Lower 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 Lower Cutoff Frequency minimum of 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 minimum setting of 100Hz over the Lower Cutoff 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
18. dow 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 T 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 out the dip 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 dip to produce the following display Abort 2250 Hz Atten Figure A 10 6 Spectral Graphic Define Edit Region 8 Now draw in the new portion of the filter curve using mouse clicks as in Step 4 above roughly as shown below Abort 2109 Hz Atten Figure A 10 7 Spectral Edit In Progress 9 Complete drawing the new portion of the filter curve as shown below by drawing points all the way to the right edge of the edit region Edit Normalize Undo Cancel b i 2355 Hz Atten Figure A 10 8 Completed Spectral 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 f
19. ften the mouse may be plugged into one serial port and the second will have nothing attached You may need to use a 25 pin to 9 pin serial adapter to attach the cable to your computer s serial port Figure 5 4 Transfer Cable Serial Connector 5 Next take the IDC end of the PicoDAC Transfer Cable and attach it to the appropriate connector on the PicoDAC The correct header is located at the front of the PicoDAC and is the set of 10 pins on the right See Figure 5 6 for the correct location Make sure that the cable is pointing away from the battery Figure 5 5 Transfer Cable IDC Connector Figure 5 6 PicoDAC IDC Header Figure 5 7 Attaching IDC Connector to PicoDAC Figure 5 8 A Properly Connected Transfer Cable 6 Reattach the power cable and power the PicoDAC ON Run the PicoDAC Configuration Utility and load the new settings into the PicoDAC It is possible to leave the input and output cables attached when loading the new filter settings into the PicoDAC One good way to check if the filter settings are correct for your application is to transfer the new configuration while the PicoDAC is running and listen to the results The important thing to remember is to power the unit OFF and remove all cables when reattaching the top cover and rear bezel 7 After the new settings have been loaded into the PicoDAC power the unit OFF remove the power cable remove the transfer cable and replace the top cover Ap
20. gured in the PicoDAC software are stored in this file The next time the PicoDAC software is run its settings are retrieved and you are able to pick up where you left off 4 0 RECALLING FILTER CONFIGURATIONS 4 1 Open File Dialog Box Application To save time configuring control settings in the PicoDAC control settings 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 PicoDAC systems using floppy disks Open a setup from a disk file as follows 1 Click on File on the PicoDAC menu bar When the pulldown menu appears click on Open or click on the open file folder icon on the toolbar This will cause the following window to appear Look in SJ PicoDAC laa default pdc laa Factory Default Configuration pdc la Tape Enhancement pdc la Wire Tap pdc File name Files of type PicoDAC Files Tode v Cancel Open as read only Figure 4 1 Recall Setup File Window 2 If you desire to place the setup file into a different drive such as a floppy drive or directory use the Save in drop down selection box If you select a drive that is not ready an error message will be generated 3 Once the desired setup file name has been f
21. he 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 LC E3 Cutoff Frequency Stopband Attenuation 300 Hz 30 dB pi Dit Transition Slope J 40 reer EH Figure A 3 1 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 100 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 Attenuation Cutoff Frequency are ultimately attenuated Stopband attenuation is adjustable from 12dB to 60dB in 1 dB steps Transition Slope 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 Transition Slope is set to minimum Note that the indicated value changes depending upon Cutoff Frequency and System Bandwidth A graphical description of the highp
22. hich frequencies above the Cutoff Attenuation Frequency are ultimately attenuated Stopband attenuation is adjustable from 12dB to 60GB 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 but will allow more precise removal of high frequency noises Note that the indicated value changes depending upon Cutoff Frequency and System Bandwidth A graphical description of the lowpass filter and its controls is given below Figure A 2 2 Lowpass Filter Graphical Description 3 0 HIGHPASS FILTER Application 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 100 Hz can be incrementally increased until the quality of the voice just begins to be affected achieving maximum elimination of low frequency noise T
23. ilter is being recalculated When the calculations are complete the mouse cursor and the buttons in the Spectral Graphic control window will return to normal appearance 10 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 E3 EI Normalize Cancel OK d if 914 Hz Atten Figure A 10 9 Normalized Spectral Graphic Equalizer This completes the Spectral Graphic Equalizer mini tutorial 11 0 IMPORTED COEFFICIENT FILE Application The Imported Coefficient file is available for inputting filters created via other synthesis software Several math software packages such as Matlab are available from other vendors These packages provide high level math functions for computing complex filters Once the filters have been calculated the results can be stored in floating point format in a standard hex file The PicoDAC Configuration Software is able to import these files and convert them into the format necessary for transfer into the PicoDAC Files of type Text Files txt Cancel Open as read only Figure A 11 1 Open Imported Coefficient File Dialog Box Descrip
24. l 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 maximum 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 3 LS Cutoff Frequency Stopband Attenuation 2500 Hz 30 dB A AA Transition Slope 327 dB Octave a Cancel 4 gt Figure A 2 1 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 Stopband Specifies amount in dB by w
25. ming the PicoDAC The COM port that is being searched for the PicoDAC or that is being used to transfer the configuration file will appear in the lower right corner of the Transferring Filters window As the filter file is transferred the progress bar will display how much of the total configuration file has been transferred When the transfer is complete the window will disappear and the Main Control Window will become active Pile Es Programming PicoDAC Port COM 1 Figure 2 6 PicoDAC Transfer Window Programming PicoDAC The programming of the PicoDAC can be stopped at any time by pressing the Cancel button A message window will appear telling you that the download has been aborted and that the filters stored in PicoDAC are no longer valid Because the download was stopped before it was completed the filter settings stored in the PicoDAC may no longer be usable It is advised that the PicoDAC be reset by using the Reset button located on the back panel and a valid configuration be transferred to the PicoDAC by repeating the Program PicoDAC procedure mentioned above 3 0 STORING FILTER CONFIGURATIONS 3 1 Save File Dialog Box Application To save time configuring the PicoDAC 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 pr
26. moving 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 60dB 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 Lower Cutoff Frequency Upper Cutoff Frequency ok 2000 Hz 2500 Hz ox H f du fee Transition Slope Stopband Attenuation Lower 131 dB Octave Upper 327 dB Octave SE g ML Y Figure A 5 1 Bandstop Filter Control Window 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 Upper Cutoff Frequency Transition Slope Stopband Attenuation Frequency is 0 Hz while the maximum Lower Cutoff Frequency is 100 Hz below the Upper Cutoff Frequency Lower Cutoff Frequency can be adjusted in 1 Hz steps NO
27. nennen 27 Figure A 2 1 Lowpass Filter Control Wumdow 29 Figure A 2 2 Lowpass Filter Graphical Descrpton Rennen 30 Figure A 3 1 Highpass Filter Control Wimdow nennen nn nennen 31 Figure A 3 2 Highpass Filter Graphical Description 32 Figure A 4 1 Bandpass Filter Control Wmmdow nennen nennen 34 Figure A 4 2 Bandpass Filter Graphical Descrpoton nennen 35 Figure A 5 1 Bandstop Filter Control VWumdow 37 Figure A 5 2 Bandstop Filter Graphical Descrptpon nennen 39 Figure A 6 1 Comb Filter Control Window cccccccccccccccccnncncnnnnnnnnnnnnnnnnnnnnnnnncnnnnnnnos 41 Figure A 6 2 Comb Filter Graphical Description nennen 43 Figure A 7 1 Notch Filter Control Window cccccccccccccccccccccnnncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnos 45 Figure A 7 2 Notch Filter Graphical Descrpton ernennen 46 Figure A 8 1 Slot Filter Control Wumdow nennen nnnnnnnn nn 47 Figure A 8 2 Slot Filter Graphical Descrpton 48 Figure A 9 1 20 Band Graphic Equalizer Control WiNdOW sssssssnnnnneesenennnnnnnneneeenne 49 Figure A 10 1 Spectral Graphic Equalizer Wumdow 51 Figure A 10 2 New Spectral Graphic Equalizer Display 52 Figure A 10 3 Spectral Graphic Draw in Progress 53 Figure A 10 4 Completed Spectral Graphic Drauw 54 Figure A 10 5 Spectral Graphic Edit Window EE 54 Figure A 10 6 Spectral Graphic Define Edit Hegoton 55 Figure A 10 7 Spectral Edit In Progress AAA 55 Figure A 10 8 Completed Spectral Graphic Ed 56 Figure A 10
28. nt panel There are two Stages for each filter Each Stage can be customized using one of the following filter types One Channel Adaptive Filter Lowpass Filter Highpass Filter Bandpass Filter Bandstop Filter Comb Filter Notch Filter Slot Filter 20 Band Graphic Equalizer Spectral Graphic Equalizer Imported Coefficient File Pass Thru Filter Once the filter type is selected click on the Control button to bring up the control window for the selected filter This window allows you to customize the parameters which define the filter performance After selecting the values for each parameter click on the OK button Refer to Appendix A for more information on filter types and their parameters 2 3 Automatic Gain Control Radio Buttons The AGC Automatic Gain Control radio buttons are shown below Each filter can have the AGC turned off via the No AGC option or have 10dB 20dB or 30dB of AGC applied to the input signal When the AGC is active it will boost the INPUT signal by the amount specified to bring it up to an input level of 12 dB This AGC setting applies to both Stages within the Filter AGC NoAGC 10dB AGC C 20dB AGC 30dB AGC Figure 2 2 AGC Radio Buttons 2 4 Bandwidth Radio Buttons The Bandwidth radio buttons allow one of the three bandwidths 3 4 kHz 5 0 kHz or 7 5 kHz to be selected for a Filter This setting applies to both Stages Bandwidth 34kHz fe 5 0kHz OC 7 5kHz
29. ocedure Also this feature allows easy transfer of enhancement setups between PicoDAC systems using floppy disks Store a setup to a disk file as follows 1 Click on File on the PicoDAC menu bar When the pulldown menu appears click on Save As or click on the floppy disk icon on the toolbar This will cause the following window to appear Save in SJ PicoDAC laa default pdc la Factory Default Configuration pd la Tape Enhancement pdc la Wire Tap pdc File name Save as type PicoDAC Files Tode v Cancel Open as read only Figure 3 1 Save As Setup File Window 2 If you desire to place the setup file into a different drive such as a floppy drive or directory use the Save in drop down selection box If you select a drive that is not ready an error message will be generated 3 You will need to specify a filename for the setup Click on the File Name text box then type the desired filename All setup filenames must have the PDC extension thus the PDC extension is automatically included in the text box 4 Click on OK to store the setup file with the selected filename to the specified drive and directory The Open as read only checkbox is not applicable and is ignored NOTE The file default pdc is the configuration file stored in the installation directory that holds the shutdown information for the PicoDAC software When the PicoDAC software is closed whatever settings are confi
30. ormalize button allows the user to instantly move all slider controls up until the top slider is at 0dB The Make All 0dB button instantly sets all the sliders to 0dB 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 Gain 0 10 15 15 17 25 14 8 21 26 27 20 18 12 18 24 25 31 34 40 R VF ss Make All 0dB eg jen fess es gee a Pryor All Down 198 an pi el E p Cancel 40 RUGER Freq 75 150 250 350 450 550 650 750 850 950 1 1K 1 4K 1 6K 1 9K 2 2K 2 5K 2 8K 3 1K 3 4K 3 7K Figure A 9 1 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 0dB and 40 dB in 1dB steps Center Frequency Note that the Center Frequency of each band is labeled underneath each slider and that bands are more closely spaced at low frequencies Gain Indication Normalize Button Make All 0dB Button All Down 1dB Button 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
31. ound either double click it or click on OK to recall it The file will be loaded NOTE The file default pdc is the configuration file stored in the installation directory that holds the shutdown information for the PicoDAC software When the PicoDAC software is closed whatever settings are configured in the PicoDAC software are stored in this file The next time the PicoDAC software is run its settings are retrieved and you are able to pick up where you left off 5 0 TRANSFER CABLE ATTACHMENT 5 1 Connecting the Transfer Cable to the PicoDAC 1 First turn OFF PicoDAC POWER switch and remove all INPUT and OUTPUT cables To remove the PicoDAC top cover remove the thumb screws 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 A PRODAC qe INPUT OUTPUT 12v O A LO SAN POACISA POWER Fr DIGITAL AUDIO COMPANY MADE IN USA ON Figure 5 1 PicoDAC Rear Panel Thumb Screws 2 Remove the rear panel and bezel Figure 5 2 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 3 PicoDAC Top Cover Removal 4 The PicoDAC Transfer Cable has a serial connector for the computer and an IDC connector for the PicoDAC Attach the serial connector to the serial port on the computer where the PicoDAC software is running O
32. pendix A This section contains detailed information on each of the filters This information can be found in the software Help file as well 1 0 ONE CHANNEL 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 Filter Size Prediction Span 128 taps 3 samples 0010 667 milliseconds 0000 250 milliseconds a gt all gt Cancel Adapt Rate Adapt Mode Processor Output Mu 10 x2 14 Auto Residue GR gt C Fixed C Predict Figure A 1 1 1CH Adaptive Filter Control Window Description of controls is as follows Filter Size 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 taps but can be set to as high as 256 taps 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 256 taps is a good overall general recommendation Adapt Rate Used to set the rate at which the adaptive filter adapts to changing signal conditions Mathematically known as Mu A Mu of 1 x 24 14 provides very slow adaptation while a Mu of 256
33. reduction outside the passband region 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 each Cutoff Frequency to the minimum volume specified by Stopband Attenuation can also be controlled by adjusting the Transition Slope setting Lower Cutoff Frequency Upper Cutoff Frequency or 300 Hz 2500 Hz ox EU JJ IJ cancer Transition Slope Stopband Attenuation Lower 20 dB Octave Upper 327 dB Octave re ALL Y Figure A 4 1 Bandpass Filter Control Window Description of controls is as follows Lower Cutoff Frequency Upper Cutoff Frequency Transition Slope Stopband Attenuation Specifies frequency in Hertz below which all signals are attenuated 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 100 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 100 Hz below the Upper Cutoff Frequency 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 100 Hz above the Lower Cutoff Frequency while the maximum Upper Cutoff Frequency depends upon the System Bandwidth se
34. stored on to a line The PicoDAC only uses 256 coefficients for each filter stage If a file contains more than 256 coefficients those remaining after the 256 are read are ignored Conversely if a file contains less than 256 coefficients the remaining coefficients are set to zero If the coefficient file is not set in the correct format the PicoDAC software will not load the file and popup a message box informing the user When the Imported Coefficient File is selected as the filter type for the stage it s default coefficients are set up as a digital bypass Once a valid coefficient file is loaded it s data stored in the PicoDAC configuration can be stored in a settings file for later retrieval without the need of the original coefficient file NOTE Keep in mind that the sample frequency will affect the results of the filter The floating point filter coefficients are normally set up using a specific sampling frequency If the coefficients are used in a filter with a different sampling frequency the filter will be skewed Below is an example coefficient file containing 53 filter coefficients 4 387280E 003 1 262311E 002 7 795490E 003 5 957981E 003 1 444848E 002 1 2 2 416667E 001 2 2 1 919611E 003 957611E 003 674714E 002 028165E 003 060535E 002 978514E 002 120655E 003 430844E 002 407519E 002 196839E 003 991908E 002 074622E 002 256326E 003 956892E 002 286449E 002 298883E 003 050633E 002 26974
35. t Filter 20 Band Graphic Equalizer Spectral Graphic Equalizer Pass Thru Filter Floating point formatted coefficient text files can be imported as well A description of each filter type its application and a definition of the control parameters can be found in Appendix A 1 2 Installation To install the PicoDAC software simply insert the PicoDAC Installation CD into your CD ROM drive If the installation software does not automatically run after several seconds you will need to manually start the installation as follows With the PicoDAC Installation CD in your CD ROM drive click on the Start menu and then the Run option In the window that appears type X setup exe And click OK or hit the Enter key Where X is the drive letter of your CD ROM The installation program will then start Follow the directions given in the installation program Often times after the installation is complete you will be told to reboot your system Once the system has rebooted you can run the PicoDAC software by clicking on the Start Menu then the PicoDAC menu and then clicking the PicoDAC icon If the personal computer PC on which you wish to install the software does not have a CD ROM contact Digital Audio Corporation to send you the software on floppy disks 2 0 PICODAC CONFIGURATION CONTROL 2 1 PicoDAC Control Panel Dei File Help Diels l Filter5 pap Filter Fiter8 Fites Dat nei Fiter2 Fiter3 Fites
36. te that the very first click always sets the O 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 to mouse The curve will advanced the smallest step at the specified attenuation 1969 Hz Atten Figure A 10 3 Spectral Graphic Draw in Progress Complete drawing the filter curve as shown below by drawing points all the way to the right edge of the filter display area Edit Normalize Undo Cancel b i 1723 Hz Atten Figure A 10 4 Completed Spectral Graphic Draw When you have drawn the last point must be at or beyond the right edge of the filter display area the Spectral Graphic control window will return to normal appearance Suppose you decide that you would like to remove the dip which occurs in the filter curve at approximately 3000 Hz in the figure above Click on Edit to bring up the following display 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 Zessesnssnsnnssunsnnennsnnenusenunnesunung Oase dd C 25dB C 1048 C 30dB Cancel C 15dB C 35dB 3 ei a e a a E io o o E N a E Figure A 10 5 Spectral Graphic Edit Window In this win
37. 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 60 dB until the tone is observed then increase the depth 5 dB E E Notch Frequency Notch Depth 400 Hz 30 dB 11 WW Notch Width yo ty eje Figure A 7 1 Notch Filter Control Window Description of controls is as follows Notch Frequency Specifies frequency in Hertz which is to be removed from the input audio Minimum Notch Frequency is 0 Hz while maximum Notch Frequency depends upon the System Bandwidth setting Notch Frequency is adjustable in 1 Hz steps Notch Depth Depth of the notch that is generated Notch Depth is adjustable from 10 dB to 60 dB in 1 dB steps Notch Width Width of the generated notch in Hertz NOTE Minimum Notch Width varies with the System Bandwidth setting Hint A notch filter is best for stable tones It has a sharp bottom If a flatter bottom stopband is needed the bandstop filter may be preferred Also a 1CH Adaptive filter is useful in tracking varying tones A graphical description of the Notch filter and its controls follows in the figure below xy Figure A 7 2 Notch Filter Graphical Description 8 0 SLOT FILTER
38. tion of controls are follows Open File Dialog The only control available for this filter is the Open File Box Dialog Box that appears when the Control button is pressed This window allows the user to select the filter file from any location on the local computer or network The default file extension is txt If this is not the file extension of the coefficient file then click on the Files of Type selection box to choose All Files This option will allow you to see all files in the current directory Once the appropriate file is selected press OK The Open as read only is not applicable to the coefficient file and is to be ignored 11 1 Coefficient File Format The coefficient file format is restricted to only accept floating point numbers in the range of 1 0 and 1 0 If a coefficient exceeds this limitation the software will clip the coefficient to it s closest maximum Each coefficient needs to be in standard decimal notation or scientific notation The following are some examples of floating point coefficients in decimal format 0 3455 0 0008975 Scientific notation is in the form mantissaE exponent The following are some examples of floating point coefficients in scientific format 3 25E 003 0 003250 5 36E 2 0 0536 1 25E 004 0 000125 8 1234E2 812 34 clipped to 1 0 by the PicoDAC software Only one coefficient may be located on a line The coefficients can be comma separated but must still be
39. tting Upper Cutoff Frequency can be adjusted in 1 Hz steps NOTE The Upper Cutoff Frequency can never be set lower than 100 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 and the System Bandwidth 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 below the Lower Cutoff Frequency and above the Upper Cutoff Frequency are ultimately attenuated Stopband Attenuation is adjustable from 12dB to 60dB in 1 dB steps A graphical description of the Bandpass filter and its controls follows in the figure below Figure A 4 2 Bandpass Filter Graphical Description 5 0 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 is useful for re
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