Home

BOYS TOWN NATIONAL RESEARCH HOSPITAL

1. Displays seven input output sensitivity parameters AD_sensitivity cnt V the sensitivity of the A D converter in count per volt DAT sensitivity cnt V the sensitivity of the first or Left D A converter in count per volt DA2 sensitivity cnt V the sensitivity of the second or Right D A converter in count per volt MP transfer The name of a file that specifies a frequency dependent microphone sensitivity The MP_transfer file may be a text file with one frequency and sensitivity V Pa pair on each line In this case the MP sensitivity parameter is still used to scale waveforms but not frequency components levels Alternatively the MP_transfer file may be a MATLAB compatible SYSRES data file In this case the transfer function contained in the MAT file is multiplied by the MP sensitivity parameter MP_sensitivity V Pa sensitivity of the microphone in volts per pascal when it is assumed to be constant for all frequencies The value of this parameter for the ER 10C is 0 05 0 5 or 5 depending on whether the GAIN switch is set to 0 20 or 40 dB LS1_sensitivity V Pa sensitivity of the first Left receiver loudspeaker in volts per pascal LS2_sensitivity V Pa sensitivity of the second Right receiver loudspeaker in volts per pascal DPOAE Parameters that affect the DPOAE test Page 13 Buffer Size the number of samples in the DPOAE stimulus The default value is set by the parameter size
2. Page 26 Items 1 Maximum number of items for Trials axis Repeat 1 Number of times that the stimulus conditions will be repeated If the default values are satisfactory then it is not necessary for a list file to contain any of the above header lines Each stimulus condition line should contain at least seven numbers 1 Frequency of the F2 tone in Hz F2 Frequency of the F1 tone in Hz F1 Level of the F2 tone in dB SPL L2 Level of the F1 tone in dB SPL L1 Duration of averaging time not including portions rejected due to artifacts in seconds T Qe ES O Noise level stopping criterion in dB SPL Noise 7 Signal to noise ratio SNR stopping criterion at the DP frequency in dB SNR Other columns can be added to specify the frequency and level of suppressor tones the phase of the Fl tone and the attenuation on the soundcard input 8 Frequency of the F3 tone in Hz F3 9 Level of the F3 tone in dB SPL L3 10 Frequency of the F4 tone in Hz F4 11 Level of the F4 tone in dB SPL L4 12 Phase of the Fl tone in degrees lt dp 13 Attenuation on the soundcard input dB With 24 bit soundcards no attenuation hardware is needed so the equivalent input attenuation is implemented in the software prior to averaging It is easier to edit an existing list file than to create a new file in a text editor New files can be generated from within EMAV by selecting Create List File in the File menu or by not s
3. in the configuration file Rate of Clock Hz the A D and D A sampling rates samples second Sweeps per Set This parameter specifies the number of sweeps in each set for the measurement phase of the DPOAE test For efficiency the total number of sweeps averaged for each test is divided into sets with a few sweeps in each set DP Frequency the distortion product frequency to be measured The value toggles among 2 F1 F2 3 F1 2 F2 4 F1 3 F2 2 F2 F1 and F2 F1 Input Mode controls the reading and writing of sweep SWP files The value toggles among REAL TIME RECORD and PLAYBACK REAL TIME is the normal A D Input Mode with no sweep file involvement RECORD mode reads input from the A D and saves each subset of recorded sweeps to a sweep file PLAYBACK reads input from a sweep file instead of from the A D A sweep file must be opened using the File Open function to allow PLAYBACK mode Stimuli parameters related to the DPOAE stimulus Checkfit stimulus the name of the stimulus file to be used during the check fit phase of the DPOAE test Special names indicate stimuli generated by EMAV lsw produces a chirp stimulus and bbn produces a white noise stimulus Calibration stimulus The name of the stimulus file to be used during the calibrate phase of the DPOAE test Special names indicate stimuli generated by EMAV sw produces a chirp stimulus and bbn produces a white noise stimulus Calibrati
4. Check Do not map through this device 2 All other settings left at default or as configured for other devices ii EMAV Config File settings Software control file Need to choose the Indigo as compared to the CardDeluxe in the configuration file settings as shown below Indigo 23 Oct 03 DSP W DSP_CODE Indigo AD sensitivity 3566000 cnt V DAL sensitivity 15000 ent V DA2 sensitivity 15000 ent V CardDeluxe CEL 24 Oct 03 DSP W DSP_CODE CardDeluxe AD_sensitivity 856907 cnt V 4dB DAl_sensitivity 6922 cnt V 4db DA2_sensitivity 6548 cnt V 4dB Indigo IO Soundcard Setting Hardware 1 Volume control should be at max out fully rotated away from the computer Verification With the software and hardware configured as above the following results should be obtained when running the following programs TSTLAT A DOS program run from the command prompt Outstanding latency consistency all 100 clicks have a latency of 1 875ms slight deviation from this is acceptable e g a single click out of 100 with a different latency deviations more than this suggest a problem with the setup drivers SYSRES run tstlat Ist in SYSRES tstlat lst contains the following code tstlat Ist test stability of latency st 1 sr 32000 ga 0 1 zt2 0 01 na 80 go Page 37 Should get the following result amplitude 1 000 d a_mode L a d_mode L stimulus impulse SysRe
5. Load wave device configuration from sessions c GSIF Tab default setting not important for EMAV SYSRES operation i Select 128 samples d About Tab i EMAV and SYSRES function has been verified for driver and console versions 6 14 downloaded from www echoaudio com 2 On the console itself the part that looks like a graphic equalizer a Unmute m button looks raised i Virtual out channels 1 and 2 ii Analog out channels and 2 b All other inputs and outputs are muted As of February 2008 we continue to use the now obsolete MME drivers because in our tests the newer WDM drivers would not synchronize record and playback consistently The most recent WDM driver available on the manufacturer s website 5 10 3517 has reportedly reacquired consistent I O synchronization but we have not yet been verified this claim Page 36 Windows Settings software 1 Open Control Panel and Click on Sounds Speech and Audio Devices Under Sounds and Audio Devices do the following a Audio Tab i All default devices should be set at something other than the Indigo IO ii Check Use only default devices b Hardware Tab open properties for the Echo Indigo io device i General Tab Device usage should be set to Use this device enable Properties Tab Click on Indigo io wave driver under Audio Devices and then click on Properties button 1 Select Use audio features on this device 2
6. as long as these results are still displayed by selecting the File Save function 3 2 TEOAE The TEOAE test is used to measure transient evoked otoacoustic emissions in human ears The probe i e the sound source and microphone assembly should be placed in the ear prior to starting the TEOAE test When the test is started the check fit phase is immediately initiated During this phase a transient stimulus is presented to the ear and the measured response is displayed both as a waveform and a spectrum The fit of the probe in the ear canal should be adjusted to obtain the flattest possible spectrum A proper fit sometimes requires checking to make sure the holes in the probe tip are unobstructed and that the probe is inserted as deeply as possible in the ear canal When the fit of the probe is satisfactory press Enter to proceed to the calibration phase of the test During this phase the program will automatically adjust the output level to achieve a specified target level Further correction of the stimulus waveform in order to reduce the nonlinear stimulus artifact can be initiated by pressing R Both the level adjustment and artifact correction are optional Other aspects of the stimulus presentation e g number of sweeps and artifact rejection threshold can be modified during the calibration phase When the calibration adjustments have been completed press Enter to proceed with the measurement phase of the test After the measuremen
7. 5 or 5 depending on whether the GAIN switch is set to 0 20 or 40 dB LS1_sensitivity 5 Sensitivity of the first Left receiver loudspeaker in volts per pascal LS2_sensitivity 5 Sensitivity of the second Right receiver loudspeaker in volts per pascal PRINTER Parameters The PRINTER section begins with a line containing the word PRINTER in brackets like this PRINTER Parameters in this section relate to printing the contents of the screen The following list of PRINTER parameters includes default values Label Boys Town National Research Hospital This causes the menu bar to be replaced by the specified label during printing Replacement can be eliminated by an empty parameter setting Label Orient Landscape Printing can be formatted in one of two possible orientations Landscape or Portrait Port screen ps The printer port for a directly connected printer may be specified by name such as LPT1 Network printers may be specified by their network name e g cellinux lp Instead of a port name or network printer name this parameter may be set to a file name and screen images will be written to the specified file Type PostScript You can choose one of three printer types PostScript Color PostScript or PCL The PostScript output is suitable for including in other documents as an Encapsulated PostScript file The PCL output can be used with HP LaserJet or HP DeskJet printers TEOAE Parameters The
8. A A een Ee 13 4 3OP TIONS MENU cisco di a ie eege o eege EN 13 AS TEST MENU opti EA A AA A AA A tds 18 SEUA E E ee eege ee 18 Sl ABOUT DIALOG E 18 PANA IA AA O togtbsetieys 18 SIVIEW MODE coito a dd e aca Lees a Ss does ER di 18 O FILE TYPES negn A A AA A A A ES ELE OO SE 19 6 1 CONFIGURATION FILE scooter anita 19 SYSTEM PALACE A A ROA 19 PRINTER Parameters siii dll suite E E EEN lc 20 BNG EE EE 20 DPOAE E A A O O NN 21 PROBE Pataimetets somosta At ada aan 24 TONE gt Para Meter Ed 26 o2 LIST FIDE ci tien at oat tn eee Ae eh ee ie eee ee A eit Meena tee 26 6 3 STIMULUS FILES 20 ta A A esa A oes Os elias Ree igh ea TO da 27 GADATA FILES E 27 eler eu 28 Extended Format eo leo o e eo EE to e Eet 28 High Order Format gereent eege ere A BR 29 Mull RON 29 SFOAE A O 30 RE DOEN ER 31 ACKNOWLEDGEMENTS 3 e eege Ee 34 APPENDIX A EMAV INSTALLA TION EE 35 APPENDIX B SOUNDCARD INSTALLATION no E TA ne ncnrcnnan nos 36 APPENDIX C SOUNDCARD AND PROBE CALIBRATION AA 39 Page 2 APPENDIX D AUXILIARY FILES AAA SA A E EEE 41 APPENDIX E CAVITY CONSTRUCTION cconoorionc eaa helado E A Ee ESA 42 APPENDIX F CALIBRATION FILES cccsicieev sctiectccccncsnesttvuesctesvovecocebecbssetacubend cies idad edad 44 1DAN DI A ee een ee 47 Page 3 1 INTRODUCTION EMAV is a contraction of emission averager The user interface for the DPOAE test in EMAV is similar in style to CUBeDIS a DPOAE measurement program written by Jont Allen The m
9. Q O brass strip 1x4 in cavities coupler Page 43 APPENDIX F CALIBRATION FILES When EmAv performs in the ear calibration the stimulus waveform and two microphone responses one for each loudspeaker are stored in a CAL file When stimulus levels are specified in SIL or FPL EmAv requires additional calibration files with extensions PRB THS and THL All EmAv calibration file types have formats compatible with MATLAB version 4 data files Within the MATLAB program use the option V4 to load MAT version 4 files CAL CAL files contain the responses for a single acoustic cavity typically an ear to each of the two sound sources ina DPOAE probe CAL file variables name length type Description EMAV_CAL 1 short number of cavity response waveforms rate 1 float sampling rate Hz npts 1 short number of points in each waveform reps 1 short sweeps per set atten 1 float stimulus attenuation re maximum amplitude adsn 1 float ADC sensitivity 32 bit count volt daisn 1 float_ DAC1 sensitivity 16 bit count volt da2sn 1 float DAC2 sensitivity 16 bit count volt mpsn 1 float microphone sensitivity V Pa Scale 1 float scale factor that converts waveform to pascal stimfn nchars text stimulus filename stim npts short stimulus waveform 16 bit version ncav 1 short number of cavities 1 cal01 npts long sum of 2 reps response wav
10. SPL test tone to channel B and measure the voltage being delivered to receiver B to determine the new value for DA2_ sensitivity 7 Leave the equipment set up as in step 6 In addition disconnect the microphone cable from the ER10C and connect it to BNC T The cord now goes from the multimeter to the input of the sound card Keep LS1_sensitivity 5 set MP_sensitivity 5 feed a 1 volt rms signal from the first DAC into the first ADC by telling the program to output an 80 dB tone on channel B If the RMS pressure displayed on the screen is not 80 dBSPL then the value of the AD sensitivity parameter needs to be adjusted Take the current AD sensitivity value Options System I O Sensitivity AD_ Sensitivity times the P P pressure mPa displayed on the screen and divide by 565 69 to obtain a new value for AD_ sensitivity Probe Sensitivity Parameters 1 Set MP sensitivity Options System I O Sensitivity MP sensitivity to the value appropriate for the preamp switch setting Etym tic microphones are calibrated so that 1 microvolt rms is generated by a tone at Page 39 20 micropascal If the microphone preamp GAIN 0dB then MP_sensitivity 0 05 V Pa If GAIN 20dB then MP_sensitivity 0 5 If GAIN 40dB then MP_sensitivity 5 2 Set the ER10C up as if running subjects With the soundcard and microphone sensitivity parameters set to their proper values place the probe in a standard acoustic cavity and tell the
11. TEOAE section begins with a line containing the word TEOAE in brackets like this TEOAE Parameters in this section relate to the TEOAE test The following list of TEOAE parameters includes default values adjust M The type of the attenuator adjustment used during the calibration phase of the TEOAE test A auto or M manual chk_atten 10 Attenuation applied to the stimulus during the check fit phase of the TEOAE test Page 20 chk_swps 25 Number of sweeps to be averaged before updating the display during the check fit phase of the TEOAE test HPF1 0 The cutoff frequency Hz of a 12 dB octave high pass filter on A D channel 1 for the purpose of blocking very low frequency noise The default value is zero which disables this feature HPF2 0 The cutoff frequency Hz of a 12 dB octave high pass filter on A D channel 2 for the purpose of blocking very low frequency noise The default value is zero which disables this feature FFTref 0 Reference level used for the TEOAE spectrum display A value of 0 specifies a level per cycle reference which is the equivalent SPL level in a 1 Hz bandwidth A value of 1 species an SPL level re 20 micropascal rms target 70 The initial target for the calibration phase of the TEOAE test specified in dB ppSPL or decibels re 20 micropascal peak to peak tolerance 1 Specifies how close in decibels the calibrated stimulus should be to the target level If the difference between the measu
12. The recorded waveform is ramped off at Time2 and is set to zero after this 1 msec ramp Ramp Time ms duration of a linear ramp at the beginning and end of the window used to select the TEOAE from the measured waveform Spectrum Frequency Range Horizontal full scale range in kHz of the TEOAE spectrum display Spectrum Level Range Vertical full scale range in dB of the TEOAE spectrum display Page 16 PROBE parameters that affect the PROBE test For consistency the first two items share internal variables with the DPOAE test Buffer Size the number of samples in the DPOAE stimulus Rate of Clock Hz the A D and D A sampling rates samples second Spectrum Frequency Range Horizontal full scale range in kHz of the DPOAE spectrum display Spectrum Level Range Vertical full scale range in dB of the DPOAE spectrum display Calibration parameters that describe the calibration procedure For consistency the first four items share internal variables with the DPOAE test Sweeps per Set number of sweeps in each set for the measurement phase of the DPOAE test Number of Sweep Sets maximum number of sweep sets to be measured Stimulus File The name of the stimulus file to be used during the calibrate phase of the DPOAE test Special names indicate stimuli generated by EMAV lsw produces a chirp stimulus and bbn produces a white noise stimulus Attenuation Number of db that the calibrat
13. Value Range of List Values File Config File Section aora LE i ron AT ees SSC LL DP DP Octave ax Landscape AAA screen ss screenps O SOS ER gt E rf TI EE o o Rasto ua C wo S idC Racot JI o id r Reaction tresno 16 O d PSC S E A 1 o o Save Response Binary 15 o ee E Number of Sweep Sets 16 AAA EE or a ase EELER Buffer Size 2048 Pese fa p e E ee AR Smooth o e Stimulus File File sw s i B gees Tone Kaes SE AREA Sweeps per Sei per Set Sweeps per Set A A AA AA sre Ja mw E Pinares gt gt E HA Ao Color PostScript O e nscri Postsetipt PEL Ki 25 Y Y N pot DPOAE PROBE DPOAE PROBE DPOAE PRINTER _ PRINTER TEOAE DPOAE TONE TEOAE DPOAE TONE DPOAE SYSTEM DPOAE DPOAE DPOAE TEOAE DPOAE DPOAE TEOAE DPOAE TONE as _ PROBE DPOAE TEOAE none X TEOAE DPOAE TEOAE PROBE DPOAE TEOAE TEOAE TEOAE TEOAE PRINTER PROBE Page 33 ACKNOWLEDGEMENTS Extensive testing of the EMAV program would not have been possible without the collaboration of Michael Gorga and other colleagues at BTNRH Jon Siegel has also done extensive testing of EMAV and has provided many excellent suggestions for new program features The DPOAE test was designed to be similar to the CUBeDIS program written by Jont Allen The TEOAE test
14. a BTNRH tokenfile This file format is similar to an ILS sampled data file with additional information appended The waveforms in the TEOAE data file may be viewed with the BTNRH WavEd program and spectrographs can be generated with the BTNRH SPECTO program Page 27 The TOK file may be converted to a MATLAB compatible file using the TOKMAT program described in Appendix D The DPOAE test generates an ASCII data file with a DAT extension containing the measurements of the stimulus and distortion product levels The data file has several lines of header information followed by one data line for each stimulus condition The header lines all begin with a semi colon to distinguish them from the data lines The data lines have one of several possible formats Normal Extended High Order Multi or SFOAE The formats are described below The DPOAE test also creates a binary file with a CAL extension containing the system calibration waveforms BTNRH token file format for the two channels When the SaveBin parameter is set to Yes the DPOAE test will also create a binary file with a BIN extension that contains the response waveforms for each stimulus condition The CAL and BIN files may be deleted to save disk space if the information that they contain is not needed The names of TOK and DAT files are generated automatically The CAL and BIN files are given the same name as the corresponding DAT file The file names are based on the current
15. along the y axis of the spectrum 4 5 TEST MENU There are four tests DPOAE TEOAE PROBE and TONE on the test menu Pressing the designated letter D T P or E causes the test to begin 5 Function Keys 5 1 ABOUT DIALOG Pressing FJ is a shortcut for displaying the About dialog Besides showing version number for EMAV and the ARSC function library the About dialog also show the name of the soundcard that has been selected 5 2 DEVICE LIST DIALOG Pressing F2 displays a list of available The selected soundcard is indicated by a gt symbol While the Device List is displayed pressing a number selects the corresponding soundcard on the list Alternatively the desired soundcard may be specified as the default by adding a line saying DSP_CODE number to emav ini 5 3 VIEW MODE When results of an OAE test are displayed pressing V for View puts EMAV into a special View mode that allows the test results to be examined in more detail When DPOAE results are displayed in View mode a small vertical line cursor appears on the results of a selected stimulus condition Pressing Tab or right clicking the mouse advances the cursor to the next stimulus condition while Shift Tab or left clicking the mouse backs up to the previous stimulus condition The stimulus and response information in the upper right panel changes according to the selected condition If binary data has been saved for the DPOAE results then the signa
16. already MATLAB compatible calmat exe A DOS program that transforms an old format DPOAE calibration file CAL into a MATLAB data file calmat m A MATLAB script that displays the contents of MATLAB data file created by calmat tokmat c C source code that transforms a TEOAE data file TOK into a MATLAB data file tokmat exe A DOS program that transforms a TEOAE data file TOK into a MATLAB data file tokmat m A MATLAB script that displays the contents of MATLAB data file created by tokmat Page 41 APPENDIX E CAVITY CONSTRUCTION The probe calibration cavities are constructed from brass tubing mounted on a brass plate A tube cutter is used to cut the brass tubes in the correct lengths Super glue is used to attach the brass tubes to the base plate Once the superglue is dry epoxy resin is applied around the bottom of each cavity on the base plate in order to permanently adhere the cavities to the base plate Super glue is used in the construction of the coupler The original dimensions are given below Alternative dimensions which may be advantageous for frequencies above 10 kHz are given on the next page 11 32 in o d ZS x 3 8 in o d 0 D ON 83 54 3 40 256 185 mm 30 20 mm 0 O a O Pad cavities coupler Page 42 brass tubing 11 32 in o d 8 mm i d 3 8 in od oO 2 0 tube length 674 45 0 329 25 4 16 4 mm 30 20 mm frequency 2 32 331 431 529 7 31 kHz Y f O
17. and white with the load impedance of the ear canal red and blue superimposed The bottom middle panel shows source pressure yellow and white for the sound sources and load in the ear pressure measured by the sound sources red and blue The bottom right panel is the response window It shows a spectral display of a running average of the stimuli and response components of ear canal pressure The A B average is light blue and the A B noise is in pink The middle left display contains information regarding the current stimulus condition The number in parenthesis represents the number of one quarter second sweeps in each sub average The upper right panel contains information regarding the most recently completed condition in blue and information regarding the current condition in white at the bottom of the panel Page 8 3 TESTS EMAV tests perform synchronous averaging and require access to a soundcard that has the capability to synchronize input and output consistently EMAV can also retrieve and display the results of previously saved OAE measurements using the File Open function This capability does not require a special soundcard however only files in the current working directory can be opened When displaying the results of a previous measurement the patient subject information can be modified 1f desired and the modifications saved to the file using the File Save function A hard copy of the EMAV screen can be obtained at a
18. data format each data line contains the following numbers Fm refers to the frequency of the modulation of F1 1 F2 frequency Hz F1 frequency Hz Level measured at the F2 frequency dB SPL Level measured at the Fl frequency dB SPL Total duration of sweeps accepted for averaging sec Signal level at the F2 Fm frequency dB SPL Signal level at the F2 Fm frequency dB SPL Signal level at the F1 Fm frequency dB SPL Signal level at the F1 Fm frequency dB SPL Nee PO aes A Ge aS h o Signal level measured at the DP frequency dB SPL 11 Noise level measured at the DP frequency dB SPL 12 Phase of the DP frequency component in degrees relative to onset of the stimulus deg If a suppressor was presented the next eight numbers are F3 L3 N3 lt 3 F4 L4 N4 and lt 4 where lt denotes the phase of that component The next two numbers are the L1 and L2 that were specified in the list file If a suppressor was presented the next two numbers are the L3 and L4 that were specified in the list file The next two numbers are the output voltages V1 and V2 in dB re 1 mV If a suppressor was presented the next two numbers are the output voltages V3 and V4 in dB re mV Page 30 7 EMAV PARAMETERS The following table contains parameters that can be used in list and configuration files The default values specified in the EMAV manual are set by a function within EMAV that is called when the program starts The c
19. date and a sequence number The file name begins with the last two digits of the current year followed by a single letter corresponding to the month A January B February etc then the day within the month and finally the sequence number There are 777 possible sequence numbers 00 01 99 AA AB ZZ and The current sequence numbers for both TOK and DAT files are stored in a file called emav cnt A new file name is first compared with files in the current directory and the sequence number incremented until no existing file is found with the same name Normal Format In the Normal data format each data line contains 10 numbers The header line above the data line header indicates the DP component When the calibration is performed in FPL or SIL and Normal Format is selected FPL and SIL voltages are not reported in the DAT file 1 F2 frequency Hz F2 F1 frequency Hz F1 Level measured at the F2 frequency dB SPL L2 Level measured at the Fl frequency dB SPL L1 Total duration of sweeps accepted for averaging sec T Signal level measured at the DP frequency dB SPL Ld Noise level measured at the DP frequency dB SPL Ndp Reproducibility defined as the cross correlation between partial averages A amp B Rep SOs OO es SO E SOD PS Phase of the DP frequency component in degrees relative to onset of the stimulus deg lt dp 10 Total averaging time including rejected sweeps and pauses s
20. downloads emavtm pdf Examples of data and list files along with a few related DOS programs are at http audres org downloads emav zip See Appendix D Several files that may facilitate the use of EMAV with MATLAB are at http audres org downloads emav mat zip Linux The Linux version of EMAV is available at http audres org emav linux zip The executable program file emav should be placed in usr local bin The configuration file emav ini should be edited to have the desired default parameter values and be placed in a subdirectory created for EMAV data files EMAV uses the X window system to provide a graphical user interface under Linux and an ALSA driver is assumed to be available for the soundcard to be used with EMAV The Linux version of EMAV has been tested with Mandriva Linux 2008 and the Indigo IO soundcard Page 35 APPENDIX B SOUNDCARD INSTALLATION CardDeluxe The CardDeluxe is manufactured by Digital Audio Labs http www digitalaudio com Connection of the CardDeluxe to the ER 10C requires three cables that each have a mono 4 phone plug TS at one end and a BNC connector at the other end Windows The CardDeluxe can perform synchronous averaging using its original MME Windows drivers In the device properties for this soundcard the following configuration changes should be made Under the Configuration tab set the Record mode to lock to playback and check to see that the 24 bit mode is set
21. meter Make sure the function selector is set to AC 3 Connect the BNC T connector to the multi meter via the double banana BNC connector Connect a second BNC T connector to the first BNC T connector 4 Connect the REC1 cable from the computer output of sound card to one side of the BNC T connector Connect the other side of the BNC T connector via the BNC to BNC cable to the REC1 input of the ER10C 5 Set LSI sensitivity 5 Options System 1I O Sensitivity gt LS1 so that the program will think that 1 volt rms generates 0 2 pascal 80 dB SPL of sound pressure Use the Tone test Test gt Tone to tell the program to generate an 80 dB SPL test tone on channel A Set the duration parameter so that you have enough time to read the multi meter The voltage displayed on the multi meter is the voltage being delivered to receiver A If this voltage is not exactly 1 volt rms then the DAI sensitivity needs to be changed Divide the current DAT sensitivity Options System I O Sensitivity gt DA 1 by the voltage just measured to obtain a new value for DAT sensitivity Enter the new DAI setting and repeat step 5 making sure that 1 0 volt is measured 6 To determine DA2 sensitivity follow the procedure outlined in step 5 Disconnect the REC1 cable from the BNC _T connector and connect the REC2 cable in its place Connect the other side of the BNC T connector to the REC2 input of the ER10C Set LS2_sensitivity 5 output an 80 dB
22. name of the stimulus file used for the measurement phase of the TEOAE test The default name ssw tells EMAV to generate a short sweep stimulus Checkfit Stimulus the name of the stimulus file used during the check fit phase of the TEOAE test When the name is ssw EMAV generates a short sweep stimulus Artifact Rejection and Response Filter parameters related to artifact rejection and response filter Hi Pass Filter Frequency Hz The cutoff frequency Hz of a high pass 12 dB octave filter applied to the response waveform to improve the signal to noise ratio The signal pass band is between Fl and F2 Lo Pass Filter Frequency Hz The cutoff frequency Hz of a low pass 12 dB octave filter applied to response waveform to improve signal to noise ratio The signal pass band is between Fl and F2 Rejection Threshold mPa Initial threshold in millipascal for artifact rejection during the measurement phase of the TEOAE test The threshold value may be modified during the measurement phase by using the left or right cursor keys Start Time ms The beginning of the response or echo interval of the recorded waveform specified in milliseconds from the onset of the stimulus The recorded waveform is ramped on msec prior to Timel and is set to zero prior to this 1 msec ramp End Time ms The end of the response or echo interval of the recorded waveform specified in milliseconds from the onset of the stimulus
23. program to generate an 80 dB SPL tone on channel A The RMS pressure displayed on the screen should be 80 dBSPL If not then adjust the LSI sensitivity value until it is Don t worry about being too accurate the correct value varies considerably with frequency and choice of acoustic cavity 3 Repeat step 2 on channel B to adjust LS2_ sensitivity Reminder All new sensitivity values need to be saved in the ini file Any values changed through the menu in EMAV will revert to the default values in the ini file when EMAV is reopened Page 40 APPENDIX D AUXILIARY FILES Examples of data and list files along with a few related DOS programs are at http audres org downloads emav zip Here s a list of the files included 92L21D00 CAL In the ear chirp response for 92L21D00 DAT 92L21D00 DAT DP gram with five F2 frequencies in a normal hearing ear from 1992 92L21D01 CAL Cavity chirp response for 92L21D01 DAT 92L21D01 DAT Same stimuli as used for the DP gram in 92L21D00 DAT but measured in a cavity 92L21D03 CAL In the ear chirp response for 92L21D03 DAT 92L21D03 DAT DP filter function for 2 F1 F2 with F2 4000 Hz 92L21D04 CAL In the ear chirp response for 92L21D04 DAT 92L21D04 DAT DP filter function for 3 F1 2 F2 with F2 4000 Hz 93C25D00 CAL In the ear chirp response for 93C25D00 DAT 93C25D00 DAT DP filter functions for 2 F1 F2 with F2 500 1000 2000 4000 and 8000 Hz calmat exe A DOS program
24. range of frequencies over which EMAV calculates an error value based on deviation of estimated source characteristics from ideal values Temperature Calibration cavity temperature C used in the calculation of ideal cavity impedance Default value is 25 Room Temperature If cavities are measured at body temperature 37 should be used Diameter Internal cavity diameter in centimeters used in the calculation of ideal cavity impedance Min Res If the estimated load impedance has a real part less than this value cgs acoustic ohms then it will be set equal to this value Page 17 Z_cav 0 or 1 Selects between different methods of calculating the theoretical ideal cavity impedance The default value is 0 Length Decrease Yes or No For initial estimates of cavity length these lengths may be assumed to be in decreasing order TONE parameters that affect the TONE test Buffer Size the number of samples in the stimulus buffer Rate of Clock Hz the A D and D A sample rates samples second Ramp Time ms the duration in msec of a linear ramp applied to all tones No ramp is applied unless the number of skipped sweeps is greater than zero Skipped Sweeps number of sweeps skipped before response averaging begins Skipping sweeps avoids transient responses due to stimulus onset Spectrum Frequency Range kHz maximum frequency on the x axis of the spectrum Spectrum Level Range dB range of levels
25. requires checking to make sure the holes in the probe tip are unobstructed and that the probe is inserted as deeply as possible in the ear canal 3 When the fit of the probe is satisfactory press Enter to proceed to the calibration phase of the test During this phase the system response of each channel is measured and displayed on the screen The responses of the two channels should be similar to each other If you are satisfied that the calibration was successful press Y or click on Yes to proceed to the measurement phase of the test Otherwise you can press N or click on No to repeat the check fit and calibration When the calibration waveform has been accepted EMAV will either 1 begin immediately with the first stimulus condition 2 present a list of file names for selection or 3 present a menu of parameters for generation of a new list file depending on how the list parameter is set via the configuration file or the Options menu The stimulus conditions for the DPOAE test are always obtained from a list file After the list file has been specified the presentation of stimuli begins If you have only a single set of stimulus conditions that will be used for every DPOAE test then the list file that specifies these conditions should be specified before starting the test If you have several sets of conditions then the list specification should match all of these files If you need to generate a new list file you can do this prior to sta
26. that transforms an old format DPOAE calibration file CAL into a MATLAB data file The current CAL format is already MATLAB compatible emav exe A DOS version of EMAV that can display EMAV data files but no longer has the capability to access the soundcard so does not perform any synchronous averaging functions emav ico The graphic used as an icon for EMAV emav ini Example of an EMAV configuration file fdpswp Ist A list of stimulus conditions for measuring a DP filter function for 2 F1 F2 at F2 8000 oba2 exe A DOS program that performs an octave band analysis of the response waveform stored in a TEOAE data file std let A list of stimulus conditions for measuring a DP gram with five F2 frequencies suppt Jet A list of stimulus conditions that include a third tone as a suppressor calmat exe A DOS program that transforms an TEOAE data file TOK into a MATLAB data file Several files that may facilitate the use of EMAV with MATLAB are at http audres org downloads emav mat zip Here s a list of the files included binmat c C source code that transforms a DPOAE binary file BIN into a MATLAB data file The binary file contains the response waveform for a single DPOAE stimulus condition binmat exe A DOS program that transforms a DPOAE binary file BIN into a MATLAB data file calmat c C source code that transforms an old format DPOAE calibration file CAL into a MATLAB data file The current CAL format is
27. the PROBE option is used to calculate FPL or SIL middle ear reflectance is calculated and reflectance values in dB are reported in the DAT file for F1 F2 and F3 3 4 CAVITY The CAVITY test makes the same load pressure measurement as the PROBE test but only in a single cavity or other acoustic load This test may be used to measure acoustic impedance or reflectance in an ear canal 3 5 TONE The TONE test is used more for testing the hardware than for testing ears Presentation of the tone stimulus is initiated by selecting Start Tone The level and duration of the tone can be specified Tones can be output on either one of the two channels A or B of the soundcard You can tell EMAV whether or not to remove the DC component from the response waveform You can select whether the tone is presented once or repeated The recorded response to the tone is displayed along with its calculated P P and RMS level Page 11 4 MENUS There are five major function items listed on the menu bar at the top of the EMAV screen File Info Options View and Test View puts EMAV in a special mode for examining the results of an OAE measurement in more detail The other four major functions produce submenus of additional items Most of the EMAV functions are menu driven Choose the desired item on the menu bar at the top of the screen by either pressing the designated short cut key or clicking on the menu item with the mouse cursor The s
28. to left Under the Monitor tab select only Analog Output in the Analog Output mixer section In the file EMAV INL set DSP W for specify use of the Windows driver for this soundcard set DSP_code and set the soundcard sensitivity parameters according to the procedure in Appendix C Linux The CardDeluxe is not usable under Linux because no ALSA drivers are available Indigo IO The Indigo IO is manufactured by Echo Digital Audio http www echoaudio com Connection of the Indigo IO to the ER 10C requires two cables that each have a stereo 1 8 phone plug TRS at one end and two BNC connectors at the other end Windows The Indigo IO has acceptable performance with the most recent WDM driver The I O synchronization is consistent more than 99 of the time with the WDM driver The ASIO driver provides better I O synchronization that is consistent 100 of the time EMAV can use either the WDM or ASIO driver with the Indigo IO but prefers to use the ASIO driver when it is installed Indigo IO Console software 1 Open the Console and Click on Settings Button a Driver Tab i Select The sample rate is unlocked ii Check Synchronize wave devices b Console Tab i Check the following these are the defaults and are not critical to device function i maintains the settings chosen in this setup 1 Load last session when console starts 2 Auto save session when console exits 3
29. used for artifact rejection Noise HPF Frequency Hz cutoff frequency Hz of the high pass filter applied to the difference waveform used to determine artifact rejection when HPF_type 0 fixed HPF Type Selects the type of high pass filter applied to the difference waveform used to determine artifact rejection The choices are 0 fixed 1 auto and 2 off The fixed setting tells EMAV to always use the cutoff frequency specified by HPF freq The auto setting tells EMAV to set the cutoff frequency one octave below F2 The off setting tells EMAV not to apply a high pass filter parameters related to the noise level estimate during the measurement phase NNSB The number of noise side bands This parameter specifies the number of adjacent frequency components on each side of the DP frequency that will be included in the noise level estimate during the measurement phase of the DPOAE test When the value is positive the two partial averages A amp B are added and the noise level is estimated from the combined spectrum A B When the value is zero or negative the noise level is estimated from the difference spectrum A B When the value is 0 the default value the noise level estimate is based on only the A B spectral component at the DP frequency Page 15 NESB number of noise sidebands included in the detection of noise floor separation NF_separation dB threshold in dB for rejecting sub average
30. was designed to be similar to the ILO88 program distributed by Otodynamics Tom Creutz designed the original token file format on which the TEOAE data file format was based Judy Kopun and Sarah Michael revised and expanded the 2008 version of the User s Manual Since 1994 commercial rights to the EMAV program have been licensed by BTNRH to the Bio logic Systems Corporation however the EMAV program may still be redistributed for non profit use in scientific and clinical research Page 34 APPENDIX A EMAV INSTALLATION Windows The most recent version of EMAV may be downloaded at http audres org downloads emav setup zip Inside this zip file is an installation wizard setup exe that will copy program files to your computer and place a shortcut on the Desktop It is recommended that you create a dedicated folder for EMAV data files Edit the Properties of the EMAV shortcut on the Desktop to the Start in the folder that you ve created for data files Into this folder copy emav ini from C Program Files BTNRH EMAV and any protocol Ist files that you will use with EMAV Edit your copy of emav ini to specify the correct soundcard adjust the sensitivity parameters see Appendix C and modify any default values for other EMAV parameters Having your local changes to emav ini in the data folder prevents them from being overwritten when a new version of EMAV is installed The User s Manual is online at http audres org
31. BOYS TOWN NATIONAL RESEARCH HOSPITAL EMAV Otoacoustic Emission Averager Stephen Neely Zhiqiang Liu ABSTRACT EMAV is a program for measuring and displaying otoacoustic emissions The distortion product otoacoustic emission DPOAE test features artifact rejection measurement based stopping rules and noise estimation at the same frequency as the distortion product The transient evoked otoacoustic emission TEOAE test features octave band analysis and nonlinear transducer artifact correction The PROBE test estimates Th venin equivalent impedance and pressure of the sound source EMAV uses high quality soundcards for stimulus generation and synchronous averaging for noise reduction Currently supported soundcards include Indigo IO from Echo Digital Audio and the Babyface from RME An OAE probe microphone such as the Etymotic ER 10C is required for OAE measurement Computer systems without special audio hardware can still view EMAV data files or print data displays to a PostScript or PCL printer This document describes EMAV version 3 32 Technical Memorandum 17 January 1993 Revision date January 2015 555 North 30th Street Omaha NE 68131 402 498 6700 Table of Contents 1 INTRODUCTION tonada 4 AE PI TORTA EE 4 ETES RE 9 IUDPOAE A A A A A K O AA 9 KR 10 B S PROBE ti 10 SA CAMILLE EE 11 ISTONE cutis dada cd da EE 11 ASMENUS a iS AAA EEA AO EE ono 12 An WETICE MENU uo ido did ida abies 2 12 AZ INECO MENU geet AA
32. Left Right cursor keys When calibration is complete press Enter to proceed to the measurement phase The calibration stimuli may be specified as waveform files or may be generated by EMAV The calibration response waveforms are saved in MATLAB compatible CAL files During the TEOAE measurement a countdown of number of sweeps is updated continuously The TEOAE waveform and spectrum display is updated as often as desired by pressing the space bar or will update automatically every 5 seconds You can also press Escape to terminate the test early or press F9 to suspend pause the test e g in case you need to talk to someone in the middle of the test The TEOAE responses are stored in a special binary TOK format See Figure 2 for an example of the results of a typical TEOAE measurement File Info Options Stim ntb5 ils i Neely Stephen 200nPa Y Ear L ID DOB Comments Target Value 70 0 dB ppSPL 63Pa Measured Value 79 5 dB ppSPL 189Pa Atten 19 4 dB Resid 0 66Pa Echo 2 7 dB SPL Noise 12 2 dB SPL 2 3 2 4 6 Repro 93 8 95 5 0 0 88 0 98 0 78 8 210uPs JFilenanme 92L21T00 TOK Test Date 12 21 92 Test Tine 175 sec Accepted 100 256 256 128x8 sweeps Figure 2 TEOAE test display The stimulus was a band limited click at a level of 79 5 dB ppSPL The stimulus waveform and spectrum are shown in the upper left and adjacent panels of the display The response waveform echo is shown in the large panel
33. Measurement The calibration phase of the DPOAE test presents chirps to each of the two receivers loudspeakers in sequence The program uses the measured response to these chirps to calculate the voltage needed to produce any desired sound pressure level at the microphone Press Y to accept the calibration and proceed to the measurement phase Otherwise you can press N to repeat the check fit and calibration The calibration stimuli may be specified as waveform files or may be generated by EMAV The calibration response waveforms are saved in MATLAB compatible CAL files The first step in the measurement phase of the DPOAE test is to select the stimulus conditions to be presented to the ear This may be done by creating list files that contain lists of stimulus conditions or protocols ahead of time or these files can be created through EMAV by selecting File and then Create List File If you have previously created list files and placed them in the working directory they will be displayed when you select the DPOAE test The maximum sound output of the ER 10C is limited to about 75 dB SPL unless the Preamp box is modified to bypass the receiver equalization that is normally in series with the receivers loudspeakers and which attenuates the output level at low frequencies by about 20 dB Page 4 option If you create a new list file 1t will be saved in the working directory Select from the list by using the Up Down cursor key
34. and phase deg of F3 component 41 44 Frequency Hz signal dB SPL noise dB SPL and phase deg of F4 component Page 29 The next two numbers are the L1 and L2 that were specified in the list file If a suppressor was presented the next two numbers are the L3 and L4 that were specified in the list file The next two numbers are the output voltages V1 and V2 in dB re 1 mV If a suppressor was presented the next two numbers are the output voltages V3 and V4 in dB re 1 mV 45 48 L1 L4 that was specified in the list file L3 and L4 will only be present if suppressors were presented 49 52 Output voltages in dB re 1 mV for L1 L4 calculated using the calibration procedure specified in the list file SPL FPL or SIL V3 and V4 will only be present if suppressors were presented When measurements are made in FPL or SIL the following columns are added to the DAT file 53 56 FPL L1 L4 The level required to produce the desired level at the eardrum when FPL is used to calibrate L3 and L4 will only be present if suppressors were presented 57 60 SIL L1 L4 The level required to produce the desired level at the eardrum when SIL is used to calibrate L3 and L4 will only be present if suppressors were presented 61 64 RFL R1 R4 Middle ear reflectance dB calculated from measurements made during the sound source calibration for FPL R3 and R4 will only be present if suppressors were presented SFOAE Format In the SFOAE
35. anel The upper right panel reports the frequency of the first notch in the spectrum for each of the two sound sources followed by the estimated tube lengths which are calculated from the frequency of the first notch Results for each cavity are on a separate line The error term associated with the estimated Th venin equivalent source pressure and impedance is reported for each sound source An error value less than one indicates a good calibration less than 0 1 is very good The THS file named at the bottom of the panel contains the Th venin equivalent source impedance and pressure for the two sound sources The middle panel shows superimposed the calibration waveforms for each of the 5 cavities The bottom left panel shows the estimated source impedance magnitude for the two sound sources The bottom middle panel shows the estimated source pressure for the two sound sources When the impedance and pressure curves are not as smooth as those shown here rerunning the PROBE calibration should be considered The bottom right panel is the measured spectra of all the cavities in SPL superimposed Page 7 Load impedance if required is determined during the in the ear calibration phase of the DPOAE test with the probe assembly in the subject s ear canal Following the check fit phase load pressure is measured Ear canal pressure combined with previously determined Th venin source characteristics provides the necessary information to calculate load i
36. at the lower left of the display The response spectrum to the right of the waveform indicates a response peak of 20 dB Lps at about 2 kHz and a noise floor about 20 dB below the response The overall echo level is 2 7 dB SPL and overall noise level is 12 dB SPL 2 When the adjustment is turned on you can also try pressing R to apply an error correction to the last part of the stimulus This residual error correction REC is designed reduce the stimulus artifact due to transducer i e receiver nonlinearity The REC is computed by inverse filtering the residual in the stimulus interval of the waveform that remains after adding the four parts of the response The inverse filtered residual is added to a stored correction signal that is added to the fourth part of the stimulus waveform The REC process requires several iterations and is still somewhat experimental Although REC helps to make the ER 10C usable for TEOAE measurements a better solution would be to use a more linear sound source Page 6 Probe Calibration and Measurement The probe option allows EMAV to calibrate stimuli using Forward Pressure Level FPL or Sound Intensity Level SIL instead of Sound Pressure Level SPL Theoretically SIL and FPL provide measures of stimulus level that better indicate what reaches the eardrum because they are not affected by standing waves SIL and FPL calibration both require that the acoustic load impedance of the ear canal be measur
37. cies an SPL level re 20 micropascal rms HPF1 0 The cutoff frequency Hz of a 12 dB octave high pass filter on A D channel 1 for the purpose of blocking very low frequency noise The default value is zero which disables this feature HPF2 0 The cutoff frequency Hz of a 12 dB octave high pass filter on A D channel 2 for the purpose of blocking very low frequency noise The default value is zero which disables this feature HPF freq 200 When HPF type is FIXED the high pass cutoff frequency for artifact rejection is specified by HPF _freq in Hz HPF_type AUTO Selects the type of high pass filter applied to the A B response difference only for the purpose of determining artifact rejection The choices are FIXED AUTO or OFF When FIXED the high pass cutoff frequency is specified by HPF_freq When AUTO the high pass cutoff frequency is one octave below F2 Level_Unit SPL Determines the interpretation of stimulus levels in list files Level_ Unit may be set to SPL SL V FPL or SIL SPL dB indicates stimulus level re 20 uPa rms SL dB indicates stimulus level relative to subject threshold which must be specified in the Info menu V indicates peak voltage FPL and SIL dB indicate forward pressure level and sound intensity level respectively and require the presence of a THL file Page 22 list param Ist The name of the parameter list file that specifies the stimulus conditions to be presented during the measurem
38. duce error when determining Th venin equivalent source characteristics Max_Len 12 Tells EMAV that no cavity length will exceed this maximum value cm minres 0 Minimum cgs acoustic ohms of the real part of the estimated load impedance Neav 5 Number of calibration cavities which must be more than 1 Niter 100 Number of iterations when improving cavity length estimates Nsre 2 Number of sound sources Page 25 scope 8192 Allows the waveform display to show less than the entire stimulus interval during the calibrate phase of the DPOAE test smooth 0 Number of points included when smoothing Th venin impedance and pressure surge 8 Number of iterations when determining surge gain which is an estimate of the ratio of calibration cavity diameter to load cavity diameter When surge 0 the ratio the diameters are assumed to be equal temp 25 Specifies temperature degrees Celsius of calibration cavities write_txt Y Tells EMAV to write estimated Th venin source and load characteristics both left and right channels to text files ths1 ths2 thl1 and thl2 suitable for plotting The default value is Y for yes The alternate values is N for 173 no TONE Parameters The TONE section begins with a line containing the word TONE in brackets like this TONE Parameters in this section relate to the TONE test duration 1 Specifies the duration of
39. e ear reflectance dB calculated from measurements made during the sound source calibration for FPL R3 and R4 will only be present if suppressors were presented High Order Format The High Order data format is identical to the Extended data format except that 2 F2 F1 distortion component is replaced by the 5 F1 4 F2 component 15 17 Signal dB SPL noise dB SPL and phase deg at the 5 F2 4 F1 frequency Ld Ndp lt dp Multi Format The Multi data format is similar to the Extended data format with additional distortion frequencies related to suppressor tone interaction It was designed to explore the placement of F3 and F4 immediately adjacent to F2 Assuming that suppressor tones are enabled there are 44 numbers on each line in the Multi format The first twenty numbers are the same as in the Extended format Here is a description of numbers 21 44 21 23 Signal dB SPL noise dB SPL and phase deg at the 2 F1 F3 frequency Ld Ndp lt dp 24 26 Signal dB SPL noise dB SPL and phase deg at the 2 F3 F1 frequency Ld Ndp lt dp 27 29 Signal dB SPL noise dB SPL and phase deg at the 2 F1 F4 frequency Ld Ndp lt dp 30 32 Signal dB SPL noise dB SPL and phase deg at the 2 F4 F1 frequency Ld Ndp lt dp 33 34 Noise dB SPL and phase deg at the Fl frequency 35 36 Noise dB SPL and phase deg at the F2 frequency 37 40 Frequency Hz signal dB SPL noise dB SPL
40. e measurement phase of the DPOAE test If the file name contains a wild card character such as then a list of all matching file names will be presented for selection during the DPOAE test Level Unit Tells how EMAV should interpret the levels specifies in list files The choices are SPL sound pressure level in dB re 20 micropascal SL sensation level dB re threshold V volts FPL forward pressure level in dB re 20 micropascal and SIL sound intensity level in dB re 1 picowatt meter Display parameters related to the DPOAE measurement display Maximum Ordinate Level dB The maximum level in dB SPL on the y axis of the measurement display Page 14 Minimum Ordinate Level dB The minimum level in dB SPL on the y axis of the measurement display Maximum Abscissa Level dB The maximum level in dB SPL on the x axis of the measurement display when the abscissa represents levels Minimum Abscissa Level dB The minimum level in dB SPL on the x axis of the measurement display when the abscissa represents levels Maximum Frequency oct The maximum frequency on the x axis of the measurement display when the abscissa represents frequencies The frequency is expressed as the number of octaves relative to 1 kHz Minimum Frequency oct The minimum frequency on the x axis of the measurement display when the abscissa represents frequencies The frequency is expressed as the number of octaves relati
41. ec AvT Extended Format In the Extended data format each data line contains 24 numbers when there are no suppressor tones or 32 numbers when suppressor tones have been enabled The first 5 numbers are the same as in the Normal format 1 F2 frequency Hz F1 F1 frequency Hz F2 Measured level at the F2 frequency dB SPL L2 Measured level at the F1 frequency dB SPL L2 Se AS 5 Total duration of sweeps accepted for averaging sec T The next 15 numbers describe the signal level noise level and phase at several distortion product frequencies These numbers are grouped into 5 sets of three numbers 6 8 Signal dB SPL noise dB SPL and phase deg at the 2 F1 F2 frequency Ld Ndp lt dp 9 11 Signal dB SPL noise dB SPL and phase deg at the 3 F1 2 F2 frequency Ld Ndp lt dp 12 14 Signal dB SPL noise dB SPL and phase deg at the 4 F1 3 F2 frequency Ld Ndp lt dp Page 28 15 17 Signal dB SPL noise dB SPL and phase deg at the 2 F2 F1 frequency Ld Ndp lt dp 18 20 Signal dB SPL noise dB SPL and phase deg at the F2 F1 frequency Ld Ndp lt dp The next four numbers describe the noise level and phase at the stimulus frequencies F1 amp F2 21 22 Noise dB SPL and phase deg at the Fl frequency N1 lt 1 23 24 Noise dB SPL and phase deg at the F2 frequency N2 lt 2 The next eight numbers describe the frequency signal level noise level and phase at t
42. ed which requires that the Th venin equivalent impedance and pressure of the sound source be determined from a set of known acoustic loads The first step in FPL or SIL calibration is to estimate the source impedance and pressure A chirp stimulus is presented in SPL to each of 5 tubes of known length The length of the tubes were selected so that resonant peaks occur at 2 3 4 6 and 8 kHz See Appendix E for additional details about this set of cavities Th venin source characteristics are obtained by repeatedly solving 5 linear equations in order to minimize the difference between measured and expected pressure responses An error value less than 1 for each loudspeaker indicates a good calibration less than 0 1 is very good See Figure 3 for an example of the results of a typical probe source calibration display lsv e Probe Calibration D 0 80cm T 25 0C Pa zp 938 1809 Hz L 9 12 9 16 cm zp 1361 2789 Hz A Co fzp 1752 3543 Hz 88 4 92 cn fzp 2357 4648 Hz 67 3 70 cm fzp 3195 6371 Hz IA come errors 0 388 088 G Wrote Thevenin source file 08D18P00 THS 100 120 140 160 80 220 240 ms Inpedance 23dBLps Figure 3 PROBE test calibration display The calibration pressure waveforms from the last measured cavity are shown in the upper left panel As before the red line is from the left loudspeaker and the blue line is from the right loudspeaker The spectra of these waveforms are shown in the adjacent p
43. eforms DAC1 cal02 npts long sum of 2 reps response waveforms DAC2 sets 1 short number of sets of sweeps added in 3 19 Page 44 PRB PRB files contain the responses for more than one acoustic cavity to each of the sound sources in a DPOAE probe These cavity responses are typically used to determine Th venin equivalent source characteristics The PRB file format is identical to the CAL file format except that there are two response waveforms for each cavity with variable names calNN where NN is a sequentially incremented two digit number THS THS files contain Th venin equivalent source characteristics derived from a PRB file Crosstalk pressure is optional in the computation of source characteristics and set to zero when not computed THS file variables name length type description SRC_THV 1 short number of frequency components nf rate 1 double sampling rate Hz df 1 double frequency bin Hz dc 1 double cavity diameter cm tc 1 double cavity temperature C zs1 nf complex double DAC1 source impedance cgs acoustic ohms zs2 nf complex double DAC2 source impedance cgs acoustic ohms ps1 nf complex double DAC1 source pressure Pa V ps2 nf complex double DAC2 source pressure Pa V px1 nf complex double DAC1 crosstalk pressure Pa V px2 nf complex double DAC2 crosstalk pressure Pa V Ic1 ncav float DAC1 estimated cavities lengths cm Ic2 ncav float DAC1
44. electing any existing list files in the measurement phase of the DPOAE test 6 3 STIMULUS FILES Although EMAV generates chirps and white noise stimuli internally it may use also external stimulus files for the check fit and calibration phases of both the TEOAE and DPOAE tests The TEOAE stimulus used for calibration is always the same as the stimulus used for measurement Tone stimuli are always generated internally External stimulus files have a binary format which is essentially the same as an ILS sampled data file These files have a 512 byte header followed by the stimulus waveform The header contains information about the sample rate and length of the stimulus The waveform is written as 16 bit integers two bytes per sample The EMAV program is currently set up to use two stimulus files mtb5 ils and sweep32 ils The sampling rate of the stimulus waveform should match the sampling rate to be used for the DPOAE or TEOAE test EMAV stimulus files can be created from other waveform file formats by using the BTNRH program SDCP which runs under DOS For example to create a stimulus file from a WAV file type sdcp file wav file ils 6 4 DATA FILES The TEOAE test generates a binary data file with a TOK extension that contains three waveforms the recorded stimulus waveform and two separate measurements of the response echo waveform Patient subject information and stimulus conditions are also saved in this file The file format is
45. els of the two stimulus tones measured at the plane of the probe and the distortion product are shown in the lower left panel The frequency of F is indicated on the abscissa and its level 50 dB SPL indicated by the x symbol The frequency of F was a fixed ratio of 1 2 below Fz and its level 60 dB SPL is indicated by the symbol The level of the 2F F distortion product is indicated by the inverted yellow triangles and the noise level at this frequency is indicated by the upright green triangles The bottom right panel is the response window It shows a spectral display of a running average of the stimuli and response components of ear canal pressure The A B average is light blue and the A B noise is in pink The middle left display contains information regarding the current stimulus condition The number in parenthesis represents the number of one quarter second sweeps in each sub average The upper right panel contains information regarding the most recently completed condition in blue and information regarding the current condition in white at the bottom of the panel Page 5 TEOAE Calibration and Measurement The calibration phase of the TEOAE test allows automatic adjustment of the signal amplitude for in the ear calibration Within the calibration phase you can press A to toggle the automatic signal amplitude adjustment on and off2 The noise level rejection threshold can also be adjusted during the calibration phase using the
46. ent phase of the DPOAE test If the file name contains a wild card character such as then a list of all matching file names will be presented for selection during the DPOAE test Limit 2 Initial threshold in mPa for artifact rejection during the measurement phase of the DPOAE test The threshold value may be modified during the measurement phase by using the left or right cursor keys MaxFrqOct 4 Maximum Abscissa x axis Frequency in Octaves re 1 kHz MaxLevAbs 100 Maximum Abscissa x axis Level in dB SPL MaxLevOrd 80 Maximum Ordinate y axis Level in dB SPL MinFrqOct 2 Minimum Abscissa x axis Frequency in Octaves re 1 kHz MinLevAbs 10 Minimum Abscissa x axis Level in dB SPL MinLevOrd 40 Minimum Ordinate y axis Level in dB SPL NIC 1 The number of input channels written to BIN files Setting nic 2 tells EMAV to save the response from the second A D channel nnsb 1 The number of noise side bands specifies the number of adjacent frequency components on each side of the DP frequency that will be included in the noise level estimate during the measurement phase of the DPOAE test When the value is positive the two partial averages A amp B are added and the noise level is estimated from the combined spectrum A B When the value is zero or negative the noise level is estimated from the difference spectrum A B When the value is 0 the default
47. estimated cavities lengths cm atten 1 float stimulus attenuation dB re maximum amplitude added in v3 16 sets 1 short number of sets of sweeps added in v3 19 Page 45 THL THL files contain Th venin equivalent load characteristics derived from a CAL file and a specified THS file Characteristic impedance has the same value at all frequencies Load pressure represents desired pressure volt for SPL calibration Relative pressure represents desired pressure for SIL or FPL calibration divided by desired pressure for SPL calibration Thus relative pressure provides the scale factor required to convert an SPL calibration into an SIL or FPL calibration THL file variables name length type description LD_THV 1 short number of frequency components nf rate 1 double sampling rate Hz af 1 double frequency bin Hz z0 nf complex double characteristic impedance cgs acoustic ohms zl1 nf complex double DAC1 load impedance cgs acoustic ohms pl nf complex double DAC1 load pressure Pa V pri nf complex double DAC1 relative pressure for SIL or FPL BR nf complex double DAC2 load impedance cgs acoustic ohms pl2 nf complex double DAC2 load pressure Pa V pr2 nf complex double DAC2 relative pressure for SIL or FPL attn 1 double stimulus attenuation dB re maximum amplitude added in v3 19 sets 1 short number of sets of sweeps added in v3 19 The figure below illustrates
48. ethods used by EMAV for TEOAE tests are similar to those developed for the ILO88 OAE averager from Otodynamics EMAV was designed to provide enough flexibility to allow experimenting with new ideas while being friendly enough for routine use in a clinical setting EMAV was originally designed to use the same hardware as CUBeDIS an Ariel DSP 16 board a pair of ER 2 tube phones with a 40 dB step down transformer and an Etymotic ER 10B with 40 dB of gain Recent versions of EMAV support any Windows soundcard that has the ability to synchronize input and output The CardDeluxe from Digital Audio Labs is currently the most widely used soundcard at BTNRH for data collection The Indigo IO from Echo Digital Audio and Lynx L22 from Lynx Studio Technology are also being used Custom made cables allow these soundcards to be used with the ER 10C Under Windows EMAV may use MME WDM or ASIO device drivers however synchronous averaging requires that the soundcard synchronize input and output consistently A Linux version of EMAV is also available and uses ALSA device drivers See the Appendices for additional information about soundcard installation and calibration 2 TUTORIAL A setup wizard is available for installing the EMAV program on a Windows system See Appendix A for software installation details The most convenient way to use EMAV is to create a dedicated folder to contain all the protocol and data files associated with EMAV To de
49. he screen An error value less than one indicates a good calibration EMAV uses the acoustic impedance of the ear canal to produce the SIL or FPL that has been specified in the stimulus protocol or list file EMAV reads the desired SIL or FPL in the list file measures the SPL in the ear canal and applies the FPL SIL conversion to determine the required voltage to the loudspeaker to produce the desired stimulus level There are four steps involved in calibrating using FPL SIL 1 The internal impedance and pressure of the sound source is determined The impedance of the ear canal load is determined from an SPL measurement of the ear canal combined with the source impedance and pressure The load impedance is used convert SPL to FPL or SIL 4 The FPL or SIL calibration is used to determine the voltage presented to the loudspeakers during DPOAE measurement LA These steps are described in greater detail below Step 1 Determine source impedance and pressure The source impedance and source pressure are estimated from pressure measurements in a set of cylindrical cavities with known impedance In practice the theoretical impedance of a cylindrical cavity is so sensitive to the length of the cavity that cavity lengths are initially assumed to be only approximate and these lengths are iterated to improve agreement with the measurements The theoretical impedance of a cavity may be calculated when the length diameter and temperature of the cav
50. he suppressor frequencies F3 amp F4 These lines are only present when suppressor tones have been enabled 25 28 Frequency Hz signal dB SPL noise dB SPL and phase deg of F3 F3 L3 N3 lt 3 29 32 Frequency Hz signal dB SPL noise dB SPL and phase deg of F4 F4 L4 N4 lt 4 The next two numbers are the L1 and L2 that were specified in the list file If a suppressor was presented the next two numbers are the L3 and L4 that were specified in the list file The next two numbers are the output voltages V1 and V2 in dB re 1 mV If a suppressor was presented the next two numbers are the output voltages V3 and V4 in dB re 1 mV 33 36 L1 L4 that was specified in the list file L3 and L4 will only be present if suppressors were presented 37 40 Output voltages in dB re 1 mV for L1 L4 calculated using the calibration procedure specified in the list file SPL FPL or SIL V3 and V4 will only be present if suppressors were presented When measurements are made in FPL or SIL the following columns are added to the DAT file 41 44 FPL L1 L4 The level required to produce the desired level at the eardrum when FPL is used to calibrate L3 and L4 will only be present if suppressors were presented 45 48 SIL L1 L4 The level required to produce the desired level at the eardrum when SIL is used to calibrate L3 and L4 will only be present if suppressors were presented 49 52 RFL R1 R4 Middl
51. hort cut key is indicated on each menu item as an underlined letter For example press J to enter patient subject information Alternative short cut keys 1f any appear in parentheses at the right hand side of a menu item Within submenus an ellipsis at the end indicates that another submenu will be displayed a colon indicates that a text field will be opened for editing and an equals sign indicates that a multiple choice item will be toggled to the next value Items within a menu may be selected by using the Up Down cursor keys and pressing Enter Multiple choice items are altered by pressing Enter to toggle their value Text fields are altered by pressing Enter to open the menu item for editing When editing of a text field is complete you must press Enter again to close and accept the edited text field Use Escape to close and discard any changes to the text Use Escape also to remove any subset of menu items from the display To initiate an EMAV test press T to open the Test menu then press D for example to start the DPOAE test or press T to begin the TEOAE test These two OAE tests both consist of three phases 1 check fit 2 in the ear calibration and 3 OAE measurement If you want to measure DPOAEs in FPL Forward pressure level or SIL sound intensity level rather than SPL you must determine the Th venin characteristics of the probe first using the PROBE option 4 1 FILE MENU The File me
52. how EMAV calibration files are related to each other PRB file THS file measure derive Page 46 E EE 24 TOK Earn Ay etd Moet tos Lena 24 About EMAV eiii idea 12 AI iia 19 AD sensitivity ennei 12 EEN DND SATAA P EENE AANE A EE 17 EN UE WEE 18 Adjust Fi iaa E et 13 Alias 3 artifact rejection eeeeeceeeeeseeeteeesecseeeseenees 15 AMENA OM pesenna i de 16 Buffer SIZS vos cceetoenmceenentend 12 15 16 cal gomg cidad 19 CALD MAR EE 37 E EE 19 Calibrate Stimulus oooooonnnccnononononcconononnnocnnos 13 CalibratePhase ooonnocnococnnococonnnonnncconncnonacnos 19 calibrati Onsen orein aaua RA 11 Calibracion ide 16 Calibration attenuation ooooooocooonononcconanonnncnnss 13 Card Delux io 3 32 E EE 19 Check E 11 Checkfit Stimulus oooonooononoccononinnnccononinnnccnnos 13 CheckFit Dm aa 13 A E E 19 Chk attenere nra idas 18 Chk SWPS EE 19 COK SWS EE 18 Compute Crosstalk ceeceesceeseeseeteeeteenees 16 COUN EE 20 22 Create ListFillenaiii a iran 11 Create Load Fille 11 E E EE 12 Cl W EE 11 EEN EIERE 3 DAI sensitivity mndi ieceri 12 DA2 sensitivity coooooononoocnoonnonnoonconoconoconocnnnonnos 12 Data Fla ios 14 Data Fortis il res 14 DataFint iii he ieee ts 20 eelerer EE pt ero 18 Dima mid 16 RE O 13 Display Units ooooonncnnnnnioniocnnocononconnconocnnccnnoonnos 12 DP Frequent yon ao 12 DP Octave cocinas 14 DP freg EE 20 DPOAE cia ci 8 12 19 DS Rtg tant de ido e eerste
53. imum Ordinate Level 13 Min evADS aset wn tiie Aer raeccieenees 21 Min LevO rds tert EEEEEEE EEEEEEN EEN 21 MP sensitivity cooooooocnccnoccnonoconoconocononnoco nono nnonnos 12 MP tradi 12 Multi ti is os 26 D 11 NIT A 14 NESB iia 14 TE 21 Mein is 22 MD e cl to Dia 21 NNSB ia 14 Noli iia we 14 Normal an ias 25 27 Number of cavities totest cece 16 Number of sources to test 16 Number of Sweep Setz 16 OBA2 ie nina Ee 37 EE 21 PM A 11 Open File coa ii ada 11 o A O 18 Orientation Slots 11 OtOdYNAMICS cooocococononononnnonononoco noc noonncon nono nonnnnos 3 Para 18 DO di ic E a E n E 18 e EE 18 Ne E 18 Print serei cios da 11 PRINTER oca a 18 Printer Portes cd do ohne cote 11 Printer EE 11 Printer RTE 11 PROBE SA e arie 9 15 22 Protocol File coc is 13 E RA tes ees 15 16 21 Ramp Timer EENS o 13 TUE a de 15 21 Rate of Clock adipisa 12 15 16 Reduction Mode 14 Reduction Threshold oooonccnincnncninnnoccnnconos 14 TM citas 18 Rejection Threshold ooooooonnonnnnncnincoiononnoonos 15 Rep dius E wala ae R ane 23 Response Elter 15 Save Response Binary oooocccoconocnnoccconocnnonnnonos 14 SO ee tak EEEa 21 SCOPE aR teenie acetal aida 21 a mtn E 15 21 Sig tial EE 22 EE 12 15 22 Skipped Suwecng 17 PS i 22 Smmogth 28 it idas 16 Spec Freq Range Type 14 Spec Frequency Range ooocococccnnococononinanaconnnos 14 Spec Level Range 14 Page 48 Speckreah ange escore niecnrai aiia 22 e UE lr 14 Spect
54. int when EMAV generates a sequence number for a PRB file name The default value tells EMAV to generate files names starting with the sequence number 0 Setting count 100 causes EMAV to start generating file names with the sequence number 100 which is encoded in the last two characters of the filename as AA Page 24 Crosstalk Yes Estimate cross talk between receivers and microphone when determining Th venin equivalent source characteristics dec_length No Indicates that cavity measurements are always in order of decreasing length diacav 8 Specifies diameter mm of calibration cavities fl_erf 500 Lower limit Hz of frequency range over which the length iteration error is calculated f2_erf 8000 Upper limit Hz of frequency range over which the length iteration error is calculated Ext_Iter Extends iteration when determining Th venin equivalent source characteristics by included cavity temperature and diameter when Ext_Iter Temp or cavity termination reflection coefficient when Ext_Iter Refl FFTdB 40 The vertical range in dB of the PROBE data display FFTkHz 10 The horizontal range in kHz of the PROBE data display FFTref 1 The reference level used for the PROBE spectrum display A value of 0 specifies a level per cycle reference which is the equivalent SPL level in a 1 Hz bandwidth A value of 1 species an SPL level re 20 micropascal rms Iterate 1 Iterate lengths to re
55. ion of data memory The current version always allocates 16K words of for data which allows DPOAE size up to 2048 and TEOAE size up to 1024 refresh 5 Number of seconds between automatic screen refreshes If refresh is set to zero automatic refresh is disabled AD sensitivity 0 Sensitivity of the A D converter in count per volt When set to zero the value is calculated from ARSC registry volts full scale value DA1_sensitivity 0 Sensitivity of the first or Left D A converter in count per volt When set to zero the value is calculated from ARSC registry volts full scale value DA2_sensitivity 0 Page 19 Sensitivity of the second or Right D A converter in count per volt When set to zero the value is calculated from ARSC registry volts full scale value MP transfer Name of a file that specifies a frequency dependent microphone sensitivity The MP_transfer file may be a text file with one frequency and sensitivity V Pa pair on each line In this case the MP sensitivity parameter is still used to scale waveforms but not frequency components levels Alternatively the MP transfer file may be a MATLAB compatible SYSRES data file In this case the transfer function contained in the MAT file is multiplied by the MP sensitivity parameter MP_sensitivity 0 05 Sensitivity of the microphone in volts per pascal when it is assumed to be constant for all frequencies The value of this parameter for the ER 10C is 0 05 0
56. ion stimulus is attenuated relative to maximum output Number of cavities to test Number of test cavities used during the probe calibration phase Number of sources to test Number of sound sources Setting nsrc 1 changes the PROBE test to allow load calibration in addition to source calibration Th venin Computation parameters affecting computation of Th venin source characteristics Compute Crosstalk Yes or No Modifies the equations solved for source characteristics to include an additional variable representing crosstalk Iterate Length Tells EMAV whether to perform iterative improvement of its initial estimates of cavity lengths The default value is Y for yes Alternate values are N for no and M for maybe which prompts the user for a yes or no decision after the initial cavity length estimates are displayed Iterate T amp D Yes or No Tells EMAV whether to include cavity diameter and temperature when iterating The default value is N for no The alternate value is Y for yes Smooth Setting smooth to a number greater than zero tells EMAV to smooth its estimates of Th venin source characteristics across that number of adjacent frequencies TL erf Specifies the lower frequency limit of the range of frequencies over which EMAV calculates an error value based on deviation of estimated source characteristics from ideal values D erf Specifies the upper frequency limit of the
57. ity are known The initial cavity lengths are calculated from the frequency of first spectral notch The cavity length is assumed to be one fourth of the wavelength of the notch frequency L c f 4 where c is the speed of sound The theoretical cavity impedances and measured pressures allow a least squares estimate of source impedance and pressure The error in Page 10 this estimate indicates how much the theoretical description of the sound source and cavity impedance deviates from the combined set of measured pressures By repeating the procedure using small changes in cavity lengths the error term can be minimized The optimum source impedance and pressure are associated with the smallest error The cavity chirp response pressure waveforms are stored in a PRB file The source impedance and pressure are stored in a THS file Step 2 Determine load impedance or ear canal acoustic impedance Load impedance is calculated from 1 load pressure ITE calibration 2 source impedance and 3 source pressure Source impedance and source pressure are found in the THS file created at the conclusion of Step 1 The ear canal chirp response pressure waveforms for each sound source are stored in a CAL file The load impedance is stored in a THL file Step 3 Load impedance is used to convert load pressure SPL to SIL or FPL The SIL conversion is based on the real part of the load admittance which is called conductance The FPL conversion is propor
58. l and noise spectra that correspond to the selected condition will be displayed Ifthe binary data has not been saved in the Start In directory the Response Window will be blank When TEOAE results are displayed pressing F6 separates the two waveforms Pressing expands the waveform and contracts the waveform along the time axis When the waveform is expanded pressing Tab advances the display along the time axis and Shift Tab shifts the display in the reverse direction For either type of data pressing F7 exchanges the position of the measurement results panel and spectral display panel to allow for closer inspection of the spectra Pressing Escape exits from View mode Page 18 6 FILE TYPES 6 1 CONFIGURATION FILE The configuration initialization file is called emav ini by default and can be located either in 1 the current directory 2 the directory containing the program emav exe or 3 any directory listed in the PATH environment variable The configuration file is divided into six sections SYSTEM PRINTER TEOAE DPOAE PROBE and TONE Each section begins with a line containing the name of the section enclosed in brackets The parameters that can be given values are described below for each section The default value for each parameter is indicated Lines that begin with a semicolon in the configuration file are ignored and can be used for comments or to temporarily disable a parameter setting The letters in the parame
59. mpedance Load impedance is required to convert measured pressure in the ear canal to SIL and FPL See Figure 4 for an example of an FPL SIL calibration display 20 40 60 80 100 120 140 160 180 200 220 240 ms Impedance y 23dBLps al SN A LA LA ll a An Figure 4 FPL SIL calibration display This display is produced after in the ear ITE calibration during the DPOAE test when stimulus level is specified as SIL or FPL The conversion from SPL to SIL or FPL requires Th venin equivalent source values which are stored in a THS file after performing the calibration phase of the PROBE test The top left panel shows the pressure waveform as measured during ITE calibration The red and blue lines represent the left and right loudspeakers The red and blue lines in the adjacent panel show the spectra of these pressure waveforms calibrated in SPL per unit volt The yellow and white lines represent the same calibration spectra converted to FPL or SIL per unit volt EMAV uses the FPL and SIL calibration spectra yellow and white lines to produce stimulus levels for the DPOAE test that are calibrated to these units instead of SPL The line of text above these spectra indicates whether EMAV will use SIL or FPL calibration The middle panel contains the same pressure waveforms shown in the upper left panel The bottom left panel shows the magnitude in dB re 1 cgs acoustic ohm of the estimated internal source impedance for the two sound sources yellow
60. n 18 DSP EE 18 DSPM 3 17 UCA aaa a 23 A e ee 3 EMAV ad 8 17 32 35 Page 47 End Tame iia as 15 ER a Ds sa rn ies 3 ESCAPE ona cirio 5 rentas 12 Extended et iia 25 Extract SFOA E nasere a 11 li E EE 11 12 A DA a EE 16 IVAR i EA E 16 lee ET ET 5 FFT dB EE 20 FETKH EE 20 BR Trefs a A 19 20 22 Bile Name ri aos 11 File Vecina ca 11 Bile Ty Pena eR 11 FE QUOI ia ita 23 GREG carcasa dd a a no das 18 Hi Pass Filter Frequency ccooocoocnocnoonconnconcnnns 15 Hish Order 26 High Pass FilteL ici di 14 HPF Frequency AA gees 14 HPE Type iia 14 LN E EE 20 FIRE type cin ds 20 A a OR AE ete cha 18 20 23 HPF 2 uta 19 20 23 VO engste 12 O88 sini ia 3 Indigo lO measa getest ett 3 32 34 InputMode iii iaa 13 HEMS resaca iii ee lee 23 Iterate Lengths iii 16 Herte TD tt endo BE 16 label no esos 18 landscape nes nie E nance 18 Las rl 18 Length Decrease oooocoonncnicnnoonioncocnconnconccnnoonnos 16 level EE 23 Level Uniti seht atico Machado 13 tee EE 20 IM E meh teed ee me te Ste 20 LSI Sensitivity cionado 12 EE e citrico 12 Mira EG 22 MAXxXErqUct a set soleil uote 20 Maximum Abscissa Level 13 Maximum Frequency cccoconocncocnoonconnconoconocnnonnnos 13 Maximum Ordinate Level oooooooncnccninnn 13 MaxLevADS inserere erter ee eanit 21 Mast evChd eu NEdEENEEEedENEE dE 21 Min Resum ico 16 MinErqO cti ii teins 21 Minimum Abscissa Level 13 Minimum Frequency cecceeseeeseeseeeteenees 14 Min
61. nu lists items that perform functions related to data files screen printing and program control Open Allows existing data files to be opened for review and limited editing for example of patient subject information A submenu is presented with three items Open File causes the file specified in the File Name field to be opened or if the file name contains a wild card character it presents a list of matching files for selection File Type toggles between DPOAE DPSWP DPCAL PROBE and TEOAE Each file type has a different default filename that matches any file name with the appropriate extension DAT SWP CAL PRB or TOK File Name specifies the file to be opened or pattern with one or more wild card characters of file names to be listed for selection New Erases contents of screen resets all program variables to their initial state and re reads the configuration file emav ini containing default parameter values Print Screen Causes the contents of the screen to be printed as specified in the Printer Setup menu This command can also be invoked by pressing Ctrl P or Ctrl W Printer Setup Specifies the manner in which the screen is printed A submenu is presented with three items Printer Port specifies the port e g LPT1 of a directly connected printer a file to which the printer output will be directed or the network name of a printer on the local area network ep cellinux Ip Printer Type
62. ny time by pressing Ctrl P or by using the File Print function When printing the output can be directed to a PostScript file or printed directly to a PostScript or HP PCL printer The printer name and print format are specified in the File Printer Setup menu There are many options that allow variations in the way the OAE tests are performed For example the abscissa of the DPOAE display may be changed to L1 or L2 level to F1 F2 frequency or to Trial to allow successive trials of any stimulus conditions to be displayed sequentially from left to right EMAV menus are described in more detail in the Menus section below An EMAV configuration file emav ini allows setting defaults for most of the options that appear on menus and for other options not on the menus A complete description of the configuration file parameters appears in the Configuration File section 3 1 DPOAE The DPOAE test is used to measure distortion product otoacoustic emissions The probe i e the sound source and microphone assembly should be placed in the ear prior to starting the DPOAE test When the test is started the check fit phase is immediately initiated During this phase a calibration stimulus either a chirp or white noise is presented to the ear The measured response to this stimulus is displayed both as a waveform and a spectrum The fit of the probe in the ear canal should be adjusted to obtain the flattest possible spectrum A proper fit sometimes
63. on attenuation The internal attenuation dB applied to the stimulus during the calibrate phase of the DPOAE test The level of the calibration stimulus will be this number of decibels below the maximum possible output Suppressor an additional stimulus that is added to the second Right channel Possible values are None for no suppressor Tone for a tonal suppressor consisting of one or two tones BPN for band pass noise and XBPN for band pass noise that excludes DP frequencies Use F3 F4 L3 and L4 in the list file to specify the frequency and level of the two tones or the edges of the band pass noise Adjust F1 an option to allow the user to vary the level and phase of the first primary tone during the DPOAE test Possible values are Yes and No Ramp Time ms The duration in ms of a linear ramp applied to the beginning and end of all tones used in the DPOAE test Because the ramp must be applied prior to response averaging this feature is not enabled unless the number of skipped sweeps skips is greater than zero CheckFit Time s When this parameter is non zero the check fit portion of a test will time out after the specified number of seconds and the subsequent in the ear calibration will be accepted This feature is useful when performing self tests when the probe and computer are not in the same place Protocol File The name of the parameter list file that specifies the stimulus conditions to be presented during th
64. onfiguration file is also read when the program starts so it can change any of the default values The list file is read whenever the DPOAE test starts The parameter codes are not case sensitive Parameter Menu Name Page in Default Value Range of List SE Name Options Tab Manual Values File Section m e e po awe a ssm EES ER Mam ros Normal DataFmt Data Format Type Ex Een ae DPOAE SFOAE DP_ freq DP Frequency 14 2 F 1 F2 3 F1 2 F2 X DPOAE 4 F1 3 F2 DSP EA ssm Page 31 Config Parameter Menu Name Page in Default Value Range of List File Name Options Tab Manual Values File Section frequency EE TONE EE Boys Town Label Nati nal PRINTER Research napa level TONE limit Rejection Threshold Threshold x TEOAE wc Minima Assis et oon a a a DPOAE minres Min Min Res o PROBE mode Stimulus Presentation 0 1 2 3 4 5 Een MP sensitivity MP sensitivity 05 5 5 SYSTEM MP transfer Ge 1 a SYSTEM gt H gt TEOAE Page 32 Parameter Name ncav nic niter nnsb nsrc octave Orient Port ramp ramp ramp rate rate rate RedThr refresh repeat SaveBin scope sets sets signal size size size skips smooth SpecFreqRange stimulus suppressor sweeps sweeps target temp thsf timel time2 tolerance trefresh Type write_txt Menu Name Options Tab Page in Manual Default
65. red stimulus level and the target level exceeds this tolerance then a warning message will be displayed and the user will be required to press Y to continue Trefresh 0 Number of seconds between automatic screen refresh during the TEOAE measurement phase A value of zero the default turns off the automatic refresh DPOAE Parameters The DPOAE section begins with a line containing the word DPOAE in brackets like this DPOAE Parameters in this section relate to the DPOAE test abscissa F2 Specifies the stimulus variable used for the abscissa of the data display during the measurement phase of the DPOAE test The value may be set to F1 F2 Fd L1 L2 L3 or Trials atten 20 Attenuation dB applied to the stimulus during the calibration phase of the DPOAE test CalibratePhase Y Tells EMAV whether to include phase compensation when calibrating the stimulus The default value is Y for yes The alternate value is N for no cal_swps 16 The number of sweeps per set averaged during the calibrate phase of the DPOAE test The program always collects two sets of sweeps from each input channel so the actual number of sweeps averaged per channel during calibration will be twice the specified number calibrate lsw The stimulus file to be used during the calibration phase of the DPOAE test Special names indicate stimuli generated by EMAV lsw produces a chirp stimulus and bbn produces a white noise s
66. rting the DPOAE test using the Create List File option on the File menu or press Escape when presented with a list of filenames during the DPOAE test Some aspects of the DPOAE test can still be modified after the presentation of stimuli has begun For example pressing the left or right cursor will adjust the threshold for artifact rejection The artifact rejection threshold is displayed in the lower right corner of the screen Pressing F2 allows recalibration of the stimulus in the middle of the test Pressing F9 will suspend the test temporarily Pressing Escape will terminate the test early without discarding any recorded measurements Pressing B will terminate the current stimulus condition and return to the previous stimulus condition Pressing letter N will terminate the current stimulus condition early and proceed to the next stimulus condition 3 When compressing the foam tip prior to insertion pulling the foam away from the open end may improve acoustic measurements by creating a flatter surface at the plane of the probe 4 If a calibration has already been performed as part of a previous DPOAE test then it is possible to skip the calibration phase and proceed directly to the test phase by pressing the letter T Page 9 At the end of the test you will be asked whether the recorded data should be saved in a file Press Y or click on Yes to save this test and N or No if not Even if you choose N the test results can still be saved later
67. rum Frequency Range 15 17 Spectrum Level Range 15 17 Start Times mita aii 15 Sul is leen 13 SUIS a her eet 15 ei lee EE 16 Stimulus presentation mode 15 SUDPTES Oia nia 13 EN 22 SWEEPS E 15 Sweeps E E 12 16 SO EE 12 SYSTEM oa havin gied 17 TATOOS E EE 19 Temperatura grease 16 RRE 9 15 16 18 KE H Thevenin Computation ooooooonocinoncocnioninnnonnnonos 16 Mii ata 22 tolerances tara bel otis esate 19 TONE tt AA 23 A kee 19 PE iia TERET 18 WHE ett 22 LIVE AAA E eet 16
68. s faverages 80 samples 1024 rate 32kHz gap 100ms 09 13 2006 16 09 36 845 3 milli unit 172 9 0 00 time msec 10 00 time response avcnt 80 rms 985 8 EMAV use a loopback configuration output routed directly to the input Run TEOAE check fit protocol Should observe a single click with no small amplitude click waveforms at other latencies Linux The Indigo IO uses the ALSA driver under Linux and synchronizes I O correctly in our tests Page 38 APPENDIX C SOUNDCARD AND PROBE CALIBRATION These procedures may be used to determine values for the soundcard and probe sensitivity parameters in the configuration file emav ini New sensitivity values need to be added to the ini file and this file needs to be saved The configuration file that comes with the installation of a new version of EMAV will need to be edited to contain soundcard and probe sensitivity parameters developed for your hardware Alternatively if soundcard sensitivity parameters have been previously specified for the ARSC library then setting these parameters to zero in ini tells EMAV to use the ARSC values Soundcard Sensitivity Parameters 1 To make the soundcard sensitivity measurements you will need a multi meter double banana to BNC connector BNC to BNC cable and two BNC T connectors Im te E Ka Double Banana to BNC connector BNC T connector 2 Plug the double banana BNC connector into the COM and V Q jacks on the multi
69. s and pressing Enter at the desired protocol file Or press Escape to remove the list of previously saved protocols and create a new list of stimulus conditions Once the measurement is underway a countdown of the number of sweeps averaged is displayed The measurement of a stimulus condition is terminated when any of the three specified stopping conditions time noise signal to noise ratio specified in the list file are met The measured levels of F1 F2 and Fd are displayed on the screen in the upper right box Ld represents the emission level at the 2 F1 F2 frequency and Ld represents the noise level at the same frequency The DPOAE measurements are stored in text DAT files in a format designed to be usable with the BTNRH PLT program See Figure for an example of the results of a typical DPOAE test Stim Leg 49dBLps completed condition 3 5 pass 1 1 1 0 Pa 2000 1660 1 205 MS 60 50 10 tine 4 1 64 0 sec 2 F1 F2 1320 Hz 1 2 dp e enk kd dB SPE 10 3 27 8 20 0 dB SPL 200 ms 66dBSPL Artifact Limit 8 0 mPa kHz i Figure 1 DPOAE test display The calibration waveform using a frequency sweep stimulus is shown in the upper left panel of the display and the spectrum of this waveform is shown in the adjacent panel The upper right panel contains information in blue regarding the most recently completed condition and the print in white at the bottom of the panel is information regarding the current condition The lev
70. s due to noise floor separation Reduction Mode selects an experimental method for noise reduction Its value toggles among DP no noise reduction DPnrl1 method 1 removes mean value and DPnr2 method 2 removes trend Reduction Threshold dB apply noise reduction only when the noise estimate changes by more than this threshold TEOAE parameters that affect the TEOAE test Buffer Size Number of samples in the TEOAE stimulus The number of samples in each sweep may be up to four times this number depending on the stimulus presentation mode Rate of Clock Hz the A D and D A sample rates samples second Sweeps per Set number of sweeps in each set for the measurement phase of the TEOAE test This parameter is called sweeps in the configuration file For efficiency the total number of sweeps averaged for each test is divided into sets with a few sweeps in each set Number of Sweep Sets maximum number of sweep sets to be measured Stimulus presentation mode stimulus sequence presented for each sweep Possible values are 1 1 1 2 1 1 2 3 1 1 1 3 4 L R B and 5 L R L R B 2 Numeric patterns are generated only on the first or left D A channel and the number refers to the relative amplitude of each section of the waveform The last two patterns alternate between the two channels L amp R until the final section which is applied to both channels B Stimulus File the
71. signate a working directory before using EMAV in Windows right click on the EMAV icon on the Desktop and choose the Properties Shortcut tab In the Start in text field enter the pathway of the folder containing the necessary protocol list files that you will be using and the current configuration file Prior to data collection sound card parameters should be measured and set in the configuration file These parameters should be set for each unique hardware configuration so that the effects of different loads can be taken into account Within EMAV the only directly accessible files are those found in the current working directory All of the primary testing options in EMAV DPOAE TEOAE Probe Cavity have three phases Check fit Calibration and Measurement Check fit During the check fit phase both time and frequency representations are displayed and continuously updated Each new waveform displayed on the screen is superimposed over previously displayed waveforms The screen is cleared automatically every few seconds or whenever you press Space You can judge the quality of the fit by viewing the recorded waveform and corresponding spectra that are displayed on the screen If the fit is satisfactory press Enter or select Continue to proceed to the calibration phase Otherwise press Escape to cancel the test and return to the top level menu selection The check fit phase is similar in DPOAE TEOAE and Probe tests DPOAE Calibration and
72. t phase of the test has begun it is still possible to control some aspects of the test Pressing the left or right cursor will adjust the threshold for artifact rejection This is displayed in the lower right corner of the screen Pressing F9 will suspend the test temporarily Pressing Escape will terminate the test early without discarding any recorded measurements At the end of the test you will be asked whether the recorded data should be saved in a file Press Y or click Yes if you want to save this test and N or No if not Even if you choose N you can still save the test later by using the File Save function as long as the recorded results are still displayed 3 3 PROBE The PROBE test is used calibrate the sound source for FPL or SIL measurements Estimation of Th venin equivalent source characteristics requires measurements in a set of cylindrical cavities The default number of cavities is five Prior to initiating the Probe test the probe i e the sound source and microphone assembly should be placed in the cavity set coupler See Appendix E for instructions regarding construction of the set of cavities EMAV repeats the check fit and calibration phase for each of the cavities After the required number of calibration waveforms have been accepted EMAV estimates source pressure and source impedance based on the cavity measurements iterating if necessary The error associated with the estimation of source characteristics is displayed on t
73. ter name are not case sensitive Many of the parameters may also be set through the Options menu in EMAV Changing a parameter value within EMAV will not change the default value specified in the configuration file Refer to the Parameters table for a listing of parameters that can be included in a configuration file A majority of these parameters can also be defined through the Options menu within EMAV The descriptions of these parameters are located in the Menus section of this manual All remaining configuration file parameters not defined elsewhere are included below SYSTEM Parameters The SYSTEM section begins with a line containing the word SYSTEM in brackets like this SYSTEM Parameters in this section apply to all tests These parameters should be set for your soundcard using the instructions given in Appendix C They are specific to the sound card and the load characteristics of your hardware therefore separate configuration files may need to be required for different equipment configurations The following list of SYSTEM parameters includes default values AD_type 0 This parameter is obsolete Previously if this parameter were set to 1 the program would skip clock synchronization checks for the Ariel DSP 16 DSP W Type of soundcard W Windows DSP_code Name of the file containing DSP code that needs to be uploaded to the soundcard GREG 16 This parameter is obsolete Previously this parameter modified the allocat
74. the printer type will toggle between PostScript Color PostScript and PCL The Color PostScript option is probably the best choice when printing to a file because it can be inserted into Word documents The PCL printer type is usable with many Hewlett Packard DeskJet and LaserJet printers Orientation the printer orientation will toggle between Portrait and Landscape The Portrait option produces a smaller screen image at the top of the page The Landscape option produces a larger rotated screen image 5 An asterisk matches any number of any characters in a filename while a question mark matches only a single instance of any character Page 12 File Save Allows an open file to be written again to the same file name to save any changes made to the patient subject information When no file is currently open the File Save function is disabled Create List File Provides a menu of stimulus parameters to assist with the creation of new stimulus protocol 1 e list files for the DPOAE test Create Load File Allows creation of a new Th venin load file THL from two existing files a calibration file CAL and a probe file PRB Extract SFOAE Interprets a previously opened DPOAE data file DAT as containing responses to pairs of stimulus conditions with a suppressor and without a suppressor A new DAT file is produced that contains the response with suppressor subtracted from the response witho
75. the tone in seconds frequency 1000 Specifies the frequency of the tone in Hz HPF1 0 The cutoff frequency Hz of a 12 dB octave high pass filter on A D channel 1 for the purpose of blocking very low frequency noise The default value is zero which disables this feature HPF2 0 The cutoff frequency Hz of a 12 dB octave high pass filter on A D channel 2 for the purpose of blocking very low frequency noise The default value is zero which disables this feature level 65 Specifies the level of the tone in dB SPL The level calibration is based on the sensitivity of the speakers and not on microphone measurement 6 2 LIST FILE A list file is an ASCII file that specifies the stimulus conditions that are to be presented during the measurement phase of the DPOAE test The list file contains two sections The header contains lines beginning with a semicolon that specify aspects of the DPOAE test other than the stimulus conditions Comments may also be included in this section if preceded by a semicolon Following the list file header is a section that contains one line for each stimulus condition Refer to the Parameters table for a listing of parameters that can be included in the header of a list file A majority of these parameters can also be defined through the Options menu within EMAV The descriptions of these parameters are located in the Menus section of this manual All remaining list file parameters are defined below
76. timulus Page 21 chk_atten 10 Attenuation dB applied to the stimulus during the check fit phase of the DPOAE test chk_swps 4 Number of sweeps averaged before updating the display during the check fit phase of the DPOAE test Count 0 The starting point when EMAV generates a sequence number for a DAT file name The default value tells EMAV to generate files names starting with the sequence number 0 Setting count 100 causes EMAV to start generating file names with the sequence number 100 which is encoded in the last two characters of the filename as AA DP_freq 2 F1 F2 Relation of the distortion frequency to the primary frequencies Choices are 2 F1 F2 3 F1 2 F2 4 F1 3 F2 2 F2 Fl and F2 Fl DataFmt Normal Selects the DAT file format The choices are Normal one distortion frequency only High Order 2 F1 F2 3 F1 2 F2 4 F1 3 F2 5 F1 4 F2 Extended 2 F1 F2 3 F1 2 F2 4 F1 3 F2 2 F2 F1 Multi Extended plus 2 F1 F3 2 F3 F1 2 F1 F4 2 F4 F1 or SFOAE F2 FM F2 FM F1 FM F1 FM Only the first character N H E M or S is checked by the program FFTdB 80 The vertical range in dB of the DPOAE data display FFTkHz 8 The horizontal range in kHz of the DPOAE data display when SpecFreqRange FIXED FF Tref 1 The reference level used for the DPOAE spectrum display A value of 1 specifies a level per cycle reference which is the equivalent SPL level in a 1 Hz bandwidth A value of 0 spe
77. tional to sum of the load impedance and its characteristic or surge impedance Step 4 EMAV uses the load impedance to determine the desired SIL or FPL in the ear canal EMAV reads each stimulus level in the list file and adjusts the voltage to the speaker to produce the desired level in SPL SIL or FPL The stimulus level unit is specified in the header of the list file The files produced by the SIL FPL calibration procedure are listed below Unique files names are generated for PRB THS and THL file The Ger files are temporary are overwritten each time they are produced and may be deleted whenever desired File name When Contents PRB PROBE test Waveforms in dB SPL for all cavities and both channels THS PROBE test Th venin equivalent source impedance and pressure for both channels in 4 Hz steps Zcav0 txt PROBE test Final length estimate and internal impedance and phase for each cavity for each sound source Zcavl txt PROBE test Alternate impedance for programmer only Zcav2 txt PROBE test Alternate impedance for programmer only THS1 txt PROBE test THS file in Get format used for plotting channel 1 THS2 txt PROBE test THS file in Get format used for plotting channel 2 THL DPOAE test when Created from CAL and THS files and used to convert SPL to FPL or level unit FPL or SIL SIL This file can be recreated from the CAL and THS files at any time Reflectance When
78. ut suppressor About EMAV Displays information about the program version and authors of the EMAV program The currently selected soundcard is also displayed This function may also be invoked by pressing the F1 function key Exit Terminates the EMAV program This function can also be invoked by pressing Ctrl C 4 2 INFO MENU The Info menu allows the user to enter the patient subject information that will be stored in the data file The patient subject information in existing data files may be modified by opening the file editing the information and then saving the file using the File Save function There are seven items on the Info menu Last Name First Name Ear Left or Right ID identification number Date of Birth Threshold and Comment 4 3 OPTIONS MENU The Options menu contains parameters that affect program operation and test measurement to be viewed and modified Any changes made in the Options menu will not be retained once EMAV is closed When EMAV is reopened the parameters will have returned to the default settings specified in the EMAV configuration file emav ini Default settings can be modified in the configuration file itself There are five items on the Options menu System DPOAE TEOAE PROBE and TONE System Parameters that affect all EMAV measurements Display Units mV or mPa specifies whether information is displayed during the tests in units of sound pressure mPa or voltage mV VO Sensitivity
79. value the noise level estimate is based on only the A B spectral component at the DP frequency Octave 0 Number of octaves above the primary frequencies F1 amp F2 that are included in the stimulus This allows testing of multiple DPs simultaneously The value can be 0 1 or 2 This feature is disabled when suppressor tones are included in the stimulus ramp 10 The duration in ms of a linear ramp applied to the beginning and end of all tones used in the DPOAE test Because the ramp must be applied prior to response averaging this feature is not enabled unless the number of skipped sweeps skips is greater than zero rate 32000 The A D and D A sample rates samples second for the DPOAE test Page 23 SaveBin No When SaveBin is set to Yes the DPOAE test will also create a binary file with a BIN extension that contains the response waveforms for each stimulus condition scope 8192 Allows the waveform display to show less than the entire stimulus interval during the calibrate phase of the DPOAE test seed 68131 Random number generator seed sets 2 For efficiency the total number of sweeps averaged for each test is divided into sets with a few sweeps in each set This parameter specifies the number of sets for the measurement phase of the DPOAE test signal DP Method used to estimate the signal during the measurement phase of the DPOAE test The default method DP is to take the sum of two partial a
80. ve to 1 kHz Spectrum parameters related to the DPOAE spectral display Response Window Spec Freq Range Type the range of the frequencies can be set to FIXED or AUTO When the range is set to AUTO the maximum frequency on the x axis of the spectrum varies with the F2 frequency Spec Frequency Range kHz the maximum frequency kHz on the x axis of the spectrum when it is FIXED Spec Level Range dB the range of levels dB along the y axis of the spectrum The range is relative to the highest stimulus level If this range is too small the baseline of the spectrum will not be visible Data File parameters related to the DPOAE data file Data Format Type The choices are Normal one distortion frequency only High Order 2 F1 F2 3 F1 2 F2 4 F1 3 F2 5 F1 4 F2 Extended 2 F1 F2 3 F1 2 F2 4 F1 3 F2 2 F2 F1 Multi Extended plus 2 F1 F3 2 F3 F1 2 F1 F4 2 F4 F1 or SFOAE F2 FM F2 FM F1 FM F1 FM Only the first character N H E M or S is checked by the program Save Response Binary Specifies whether the response waveforms should be written to a binary data file Y or N DP Octave Number of octaves of the primary frequencies F1 amp F2 that are included in the stimulus The value can be 0 1 or 2 This feature is disabled when suppressor tones are included in the stimulus High Pass Filter parameters related to the DPOAE high pass filter This filter is applied only to the noise measurement
81. verages Alternate methods DPnrl and DPnr2 only apply when an experimental method of noise reduction is activated size 2048 Stimulus and response buffer size 1 e number of samples per channel in one sweep skips 1 Number of sweeps to skip before averaging to avoid recording the transient response at the beginning the stimulus SpecFreqRange Fixed The range of the frequencies can be set to FIXED or AUTO When the range is set to FIXED the maximum frequency is set by FFTkHz When the range is set to AUTO the maximum frequency on the x axis of the spectrum varies with the F2 frequency sweeps 32 The number of sweeps per set averaged during the DPOAE test The program always collects two sets of sweeps from each input channel so the number of sweeps averaged will always be a multiple of twice the specified number thsf Th venin source file name A Th venin source file is required for SIL or FPL calibration Setting ths _file ths causes EMAV to prompt for the file name when it is needed PROBE Parameters The PROBE section begins with a line containing the word PROBE in brackets like this PROBE Parameters in this section relate to the PROBE test Several parameters from the DPOAE section influence the PROBE test rate sets size sweeps mode stimulus chk atten chk swps calibrate atten cal_swps and scope To ensure consistency these parameters cannot be set in the PROBE section Count 0 The starting po

BOYS TOWN NATIONAL RESEARCH HOSPITAL

Contents

Download Pdf Manuals

Related Search

Related Contents