Psycon User`s Manual
Contents
1. rms filt noise dur A filters lpl A 5 Make the rms of total signal 80dB assuming that the max cal level is greater than 80 dB ms A rms filt noise dur A filters lpl A 5 80 Psycon 1 50 user s manual Page 11 of 112. abs Absolute value exp Exponential A a b a raised by b sqrt Sqrt root mod Modulo 7 Variable definitions As the signal construction becomes complex it is convenient to define a certain signals s or value s ahead of time and use them later The Variable Definition Tag Definition in older versions edit box serves this purpose Each line in this edit box may have the syntax of variable expression so the variable can be referred in the main signal construction For example a b 0 5 tone 440 300 0 25 tone 880 300 can be defined in the Variable Definition box and simply a b can be used in the signal box Or whitenoise500 ramp noise 500 10 can be defined above and a more complex syntax can be used in the signal construction such as am bpf whitenoise500 2000 4000 8 db 25 In a verbal expression the above signal is a bandpass noise with the duration of 500 ms and gradual ramping for 10 ms applied at the beginning and ending with cutoff frequencies of 2000 and 4000 Hz amplitude modulated by 8 Hz with the depth of 25 dB 8 Looping A single line looping can be made with the function sigma Psycon 1 50 user s manual Page 8 of 11 sigma Accumulate the signal with the given formula Syntax sigma var range formula_of_var Arguments var variable to loop range same as MATLAB format using colon If specified by two values integer spacing if specified by three v
3. 00 1000 gt A pure tone with a frequency of 500 Hz and duration of 1000 milleseconds at the full scale 0 25 tone 500 1000 gt A pure tone with a frequency of 500 Hz and duration of 1000 milleseconds with the 25 magnitude from the full scale To add two signals simply add them 0 25 tone 500 1000 0 25 tone 1000 1000 gt Two pure tones each scaled by 25 of the maximum with a duration of 1000 milliseconds are added one is 500 Hz the other is 1000 Hz If you followed thus far you would know the problem of the following expression tone 500 1000 tone 1000 1000 That s right The above expression tries to generate a signal that exceeds the full scale as a result the signal will be clipped and the desired signal will not be generated Note that psycon does not issue an error message in this case because this is technically not an error The user always has to ensure that clipping does not occur If you want to use a dB factor for scaling use the db function db Calculate the actual factor from a dB value Syntax db db_value Arguments db_value If positive it calculates the scale factor with regard to the calibrated value If negative it calculates the scale factor of the specified value Examples db 6 Scale down by 6 dB db 20 Scale down by 20 dB db 80 this specifies 20 dB down from the calibrated max level which in this case is 100dB gt equivalent to db 20 Psyc
4. Psycon User s Manual Developed by Bomjun Kwon Manual partly written by J enny Shepherd 1 year AuD student University of Utah Program Description The purpose of the Psycon Software is to generate various kinds of signals to be used in tests and research Pal PSYCON v1 16 Easyview Test ject Max Cal Level 0 dBSPL eo Open Sig Strings Save Sig Strings Tag Definitions Standard Reference Signal fixed stimulus 5S tone 440 2000 fe lll To play signal press F5 then Space Bar The waveform display window below will also open Odd ballf ariable Signal use y for variable E Figure 4 5 tone 440 2000 1 Adaptive Constant Adjus Left clicking in this box will display 0 8 1 Position on the x axis of the cursor 2 Position on the y axis of the cursor rareera 0 6 3 Rms value average level of the d F8 signal displayed in the box _ eneak Right F9 Left Step L arrow Right Step R arrow Zoom Initial Yalue Play space bar Save As keypad Right clicking in this box will show the above context menu A 0992 0994 0995 0997 0 998 1 000 1 002 1 003 1 005 1 006 1 008 Current Step of Intervals Anchored Intervals Connection to localhost 1 Introduction 1 1 Purpose of psycon To generate arbitrary sound stimuli for psychoacoustic research education by intuitive and easy syntax 1 2 Structure of psyc
5. alues the second value is the step size For an arbitrary numbers use a bracket Examples sigma i 0 4 tone 2000 200 i 100 100 ms 2000Hz tone on off with a period of 0 2 second repeating 5 times Sigma i 0 4 sigma k 0 2 tone 2000 400 i k 5 50 50 ms 2000Hz tone pips repeating three times with the period of 80 ms then the pattern repeating with the period of 400 ms for 5 times beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep Looping expressions can also be used across multiple lines in the variable definition box using one of the following if while and for if condition end while condition end for index_variable_definition end For example the following example demonstrates how a noise vocoder so called cochlear implant simulation can be defined in variable definition box this generates y freq 500 1500 4000 x wave test wav y initialization of output signal with null for i 1 4 if i signalband lpf x freq i else if i 4 signalband hpf x freq i else signalband bef x freq i freq itl end envelope lpf abs signalband 200 low pass filtering full wave rectified signal noisemod envelope noise duration envelope if i signalband2 lpf noisemod freq i Psycon 1 50 user s manual Page 9 of 11 else if i signalband2 hpf noisemod freq i else signal
6. as noise but Gaussian distributed noise instead of uniformly distributed Syntax gnoise time_marker wave Read a wav file Syntax wave wave_name Arguments wave_name name of wave file Must use double quotation marks If path is not included current folder the same directory as the psycon exe will be searched extension wav can be skipped Examples wave c soundData specialnoise Read the signal from specialnoise wav in specified directory Psycon 1 50 user s manual Page 4 of 11 fm Generate a frequency modulated tone signal Syntax fm freql freq2 mod_rate time_marker init_phase 0 Arguments freql freq2 the boundary frequencies in Hz mod_rate how many times the frequency will swing between freq and freq2 Zero indicates no swing but just linear transition from freq to freq2 time_marker same as tone init_phase The initial modulation phase between 0 and 1 0 means it begins with freq and 1 means it begins with freq2 Examples fm 500 700 4 2000 a 2 second FM tone between 500 and 700 Hz at 4 Hz Note If mod_rate is set as 0 this function generates a frequency glide tone from freq1 to freq2 silence Generate a silence signal Syntax silence time_marker Arguments time_marker same as tone Examples silence 400 silence from 0 to 400 ms silence 200 500 silence from 200 to 700 ms Note This function is necessary to generate a signal with no con
7. band2 bpf noisemod freq i freq itl end signalband2 rms signalband2 signalband scale signalband2 to maintain the same rms energy before noise modulation y y signalband2 end The function cisim does the processing described above cisim Noise vocoder cochlear implant simulation Syntax cisim signal number_of_bands 9 Non signal array An array may be defined using the bracket as used in fi lt noise 1000 2 0 2 001 1 2 02 It might also be useful to use along with the use of a tag Another example to play a musical melody C E G followed by a triad chord a C chord Tag definition mel 0 4 7 12 Signal Sigma i 0 2 ramp tone 500 2 mel i 400 i 250 10 sigma i 0 2 25 ramp tone 500 2 mel i 1200 500 10 The numbers inside of the bracket may be either an array a sequence following the notation of MATLAB or the combination of both For example x 0 2 4 6 canbe written as x 0 2 6 x 4 1 3 5 0 7 An array definition may contain other tag defined earlier for example a 4 5 6 b a 10 gt sameas 4 5 6 10 b 2 a 10 gt sameas 8 10 12 12 x sin 2 3 141592 500 0 11025 22050 This low level definition is to be used instead of the tone function But not yet supported in version 1 1 10 Indexing with tags defined Psycon 1 50 user s manual Page 10 of 11 The use of tags allows extraction of data samples or time
8. l to the right Left arrow moves display of the signal to the left in smaller steps Right arrow moves display of the signal to the right in smaller steps On number pad zooms in on signal display zooms out on signal display brings signal back to its original scale brings in Save As screen Right click with mouse while in the signal box will show the above commands Left click with mouse while in the signal box will show 3 numbers 1 number shows the position on the x axis of the cursor 2 number shows the position on the y axis of the cursor 3 number shows the rms average level of the signal within the signal box 2 Signal definition syntax 2 1 basic format in the syntax Signals are represented in a semi mathematic style i e you may add subtract multiple or divide one signal or value with another with a constraint of common Psycon 1 50 user s manual Page 2 of 11 sense for example you should not try to divide by zero The most basic form of a signal is as follows scale_factorl signal signal is either a function command such as tone or noise with a proper argument list or a mathematic formula with an array of input argument specifying the time index as if you were generating a signal in MATLAB scale_factor1 specifies the scaling of the signal if it is skipped it is presumed to be 1 full or maximum scale The simplest example of signal is as follows tone 5
9. on 1 50 user s manual Page 3 of 11 Therefore the following three expressions are equivalent 0 5 tone 300 500 db 6 tone 300 500 db 94 tone 300 500 lt Assume that the cal max level is 100dB 2 2 Time parameter time marker Most functions that generate a signal require a time parameter enclosed by a bracket which specifies the beginning and duration of the signal to generate If the signal begins at the time 0 it can be skipped and only the duration is specified without a bracket i e tone 440 300 is the same as tone 440 0 300 If two tones occur in sequence it would be as follows tone 440 0 300 tone 880 400 500 gt a 440Hz tone from 0 to 300 ms and another tone at 880Hz from 400 to 900 ms 3 Signal generation functions tone Generate a tone signal Syntax tone freq time_marker initial_phase 0 Arguments freq frequency in Hz time_marker beginning_time duration in msec If only one value it begins at 0 Examples tone 226 400 a 226 Hz tone from 0 to 400 ms tone 226 200 500 a226 Hz tone from 200 to 700 ms tone 226 400 5 226 Hz tone of 400 ms 180 degree out of phase noise Generate a white noise signal uniformly distributed random val between 1 and 1 Syntax noise time_marker Arguments time_marker same as tone Examples noise 400 a white noise from 0 to 400 ms noise 200 500 a white noise from 200 to 700 ms gnoise Same
10. on program Psycon 1 50 user s manual Page of 11 The psycon software package comes with psycon_response Psycon is for signal generation and psychoacoustic test administration and is to be used by the experimenter Psycon_response is the program for the subject it provides the instruction for the subject and collects responses from the subject While both programs communicate with each other via the network protocol the user only needs to specify the machine of the other program when launching each program to establish the connection see 1 3 Installation Run psycon120 msi this is version 1 20 it may be different for a different version for psycon and psycon_resp_setup1 0 msi for psycon_response 1 4 Signal generation and waveform display box Installation Signals are defined by psycon syntax which is explained below in signal definition edit boxes With a signal typed in the signal edit box press F5 then the signal will be plotted in the waveform display box as seen above you can bring up as many of these as signals you generate To play the signal click the waveform to play and Press Spacebar Keyboard Shortcuts while in the waveform display box F2 toggles signals of the left and right channels on the foreground of the display stereo signals only F4 displays the spectrum of the signal to remove the spectrum view press F4 again F8 moves display of the signal to the left F9 moves display of the signa
11. ower than ref wav Ipf hpf bpf bsf Syntax Arguments Examples note IIR filtering Lowpass highpass bandpass and bandstop filtering respectively Ipf and hpf require at least 2 arguments signal and edge frequency and bpf and bsf require at least 3 arguments signal and two edge frequencies The rest arguments are optional and available for tweaking detailed filter settings lpf signal freq order 8 kind 1 dBpass 5 dBstop 401 hpf signal freq order 8 kind 1 dBpass 5 dBstop 40 bpf signal freql freq2 order 8 kind 1 dBpass 5 dBstop 40 bsf signal freql freq2 order 8 kind 1 dBpass 5 dBstop 40 order Filter order Default 8 kind 1 for Butterworth default 2 for Chebyshev and 3 for Elliptic dBpass Passband ripple in dB default 0 5 dB dBstop Stopband attenutation in dB default 40 dB lpf noise 1000 2000 Lowpass noise with a cutoff frequency of 2000 Hz 8th order Butterworth hpf noise 1000 3000 6 2 Highpass noise with a cut of 3000 Hz 6th order Chebyshev bpf noise 1000 1900 2000 6 3 1 80 bandpass noise between 1900 and 2000 Hz 6th order Elliptic with 1dB ripple and 60 dB attenuation Be sure to check the IIR filter s stability Note that some filtering specs such as very narrow bandpass filtering will be difficult to obtain stable filter coefficient filt Syntax Arguments Examples Filter the
12. points smooth to avoid spectrum splatter Syntax ramp signal ramping_time Arguments ramping_time The time in ms for ramping up at the beginning and down at the end Examples ramp tone 1500 500 10 Make the tone with 10 ms beginning and ending ramping Note This uses the cosine square function for smoothing 5 Other functions for signal generation psychoacoustic procedure dur Get the duration of signal in ms Syntax dur signal Note This is used to make an argument of different expression in a complex signal length Get the length of signal in sample size Syntax length signal Note This is used to make an argument of different expression in a complex signal rand Generates a double precision random number Syntax rand max_val Note Double precision random number between 0 and max_val with a uniform distribution irand Generates an integer random number Syntax irand max_val Note Integer random number between 1 and max_val with a uniform distribution randperm Generates a randomly permuted array from to val Syntax randperm val Note An integer array from 1 to val and its order is randomly permuted is generated Psycon 1 50 user s manual Page 7 of 11 file Reads a text file that contains an array of numeric values deliminated by CR LF Syntax file text file name 6 Math functions sin Sine cos Cosine log Natural log log10 10 base log
13. scaling from defined tags i bracket originally to be used for a non signal array not a signal is OK too Integers must be used inside of brackets and they indicate the indices of the array defined see the example me 1 above note the index is zero based i e the first element is 0 not 1 For example if x is defined as a sequence with the step of 2 from 2 to 20 i e x 0 2 20 x 0 2 10 Dsameasx 0 2 4 6 8 10 gt O 4 8 12 16 20 ii parenthesis to be used for a signal yet to be implemented as of version 1 50 The values inside of the parenthesis which can be any value are in milliseconds The use of parenthesis is in one of the following formats assuming that x has been defined tM Se 2 x extracted from t1 to t2 gt t x delayed by t zero padded until t t x fast forward by t x values now before 0 truncated p time scale slowed by factor of p pitch lowered vp time scale sped by factor of p pitch increased gt A 11 Integrative examples 11 1 AM FM signal o am fm 500 1000 6 1000 3 db 15 1 second 500 1000Hz FM tone at 6 Hz also AM at 3 Hz with a modulation depth of 15dB ramp 5 am fm 500 1000 6 1000 3 db 15 10 10 ms ramped version of above signal 11 2 Speech plus filtered noise with a SNR of 5 dB wave voice rms filt noise dur wave voice filters lpl wave voice 5 Using a tag A wave voice A
14. signal with the specified coefficients filt signal num array den_array filt signal mat_file matlab_filter_variable num_array den_array Numerator or denominator coefficient arrays Must use a bracket or tag see how to use tag mat_file The matlab file mat that contains the variable specified in the 3rd argument Must use double quotation marks This could include a path Default extension is mat matlab _filter variable The matlab variable of filter coefficient generated by sptool Must use double quotation marks filt norse 1000 2 O 2 001 TI 22 0213 Filter the white noise with these coefficient arrays 2nd order IIR Psycon 1 50 user s manual Page 6 of 11 filt noise 1000 filters 1p1500 Filter the noise with the coefficients available in matlab variable lp 1500 stored in filters mat am Amplitude Modulate the signal Syntax am signal mod_rate mod_depth 1 init_phase 0 Arguments mod_rate AM modulation rate in Hz mod_depth Modulation depth between 0 no mod and 1 full mod If skipped full modulation is assumed init_phase The initial modulation phase between 0 and 1 Examples am noise 1000 8 0 5 AM of a white noise at 8 Hz with a depth of 0 5 stereo Make a stereo signal Syntax stereo signall signal2 Arguments signall and signal2 are signals in the left and right channel respectively ramp Make the beginning and ending
15. tent in some experiments step Generate a dc signal Syntax step time_marker Note This is equivalent to 1 silence time_marker necessary for windowing see below examples 4 Signal modification functions Modifications of a signal generally has the following format Function_name target signal additional arguments rms Syntax Arguments Examples Scale the signal to make the rms of specified value rms signal rms signal target_level_db rms signal ref_signal signal_ref_ratio_db Signal any valid signal target_level_db The target rms level to scale the signal This value is referenced by the maximum calibrated level the full scale of the equipment ref_signal reference signal signal_ref_ratio_db relative level with regard to reference signal rms wave voicel Obtain the rms of voicel wav in relative dB to 0 dB max rms wave voicel 80 Make the signal level to be 80 dB rrns assuming that the max calibrated scale is greater than 80 dB if not this will issue an error Psycon 1 50 user s manual Page 5 of 11 rms wave voicel MAXCAL 10 Make the signal level to be 10 dB rrns down from the full max calibrated level rms noise 1000 wave ref Scale the noise so that its rms is the same as ref wav rms noise 1000 wave ref 10 Make the noise rms 10 dB higher than ref wav rms noise 1000 wave ref 5 Make the noise rms 5 dB l
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