tomwalters@0: % method of class @signal tomwalters@0: % function sig=ci_simulate(signal) tomwalters@0: % tomwalters@0: % INPUT VALUES: tomwalters@0: % sig: @signal tomwalters@0: % tomwalters@0: % RETURN VALUE: tomwalters@0: % sigresult: @signal ` tomwalters@0: % tomwalters@0: % (c) 2003, University of Cambridge, Medical Research Council tomwalters@0: % Stefan Bleeck (stefan@bleeck.de) tomwalters@0: % http://www.mrc-cbu.cam.ac.uk/cnbh/aimmanual tomwalters@0: % $Date: 2003/01/20 18:33:51 $ tomwalters@0: % $Revision: 1.4 $ tomwalters@0: tomwalters@0: function sig=ci_simulate(sig) tomwalters@0: % stolen from AMO.m tomwalters@0: tomwalters@0: audio_sample_rate=16000; tomwalters@0: tomwalters@0: p.channel_stim_rate=900; tomwalters@0: p.audio_sample_rate=audio_sample_rate; tomwalters@0: p.analysis_rate=p.channel_stim_rate; tomwalters@0: p.num_selected = 10; tomwalters@0: p.num_bands = 22; tomwalters@0: p.electrodes=22:-1:1; tomwalters@0: tomwalters@0: p=Append_process(p,'FFT_filterbank_proc'); tomwalters@0: p=Append_process(p,'Power_sum_envelope_proc'); tomwalters@0: p=Append_process(p,'Reject_smallest_proc'); tomwalters@0: FTM=Process(p,sig.values); tomwalters@0: tomwalters@0: tomwalters@0: % Parameters for Resynthesis tomwalters@0: % -------------------------- tomwalters@0: pre.resynthesis_rate = audio_sample_rate; tomwalters@0: pre.num_bands = p.num_bands; tomwalters@0: pre.analysis_rate = p.channel_stim_rate; tomwalters@0: pre.electrodes=p.electrodes; tomwalters@0: tomwalters@0: insertion = 22; % insertion depth in mm tomwalters@0: cochlength=33 % length of cochlea tomwalters@0: elecspacing = 0.75; % spacing between electrodes in mm tomwalters@0: b = 0.3; % space constant in mm tomwalters@0: tomwalters@0: % prepare non-overlapping crossover frequencies according to Greenwood tomwalters@0: % -------------------------------------------------------------------- tomwalters@0: for i=1:23 tomwalters@0: %elec_position_base(i)=insertion-elecspacing*(i-1); % position of elec in cochlea from base [mm] tomwalters@0: crossover_position_base(i)=insertion - (elecspacing*(i-1) - elecspacing*0.5); % position between electrodes from base [mm] tomwalters@0: end tomwalters@0: crossover_position_apex=cochlength-crossover_position_base'; % position between electrodes from apex [mm] tomwalters@0: crossover_freqs_greenwood=Greenwood_x2cf(crossover_position_apex); % corresponding Greenwood frequencies tomwalters@0: % check if there are frequencies above 1/2 sampling rate, tomwalters@0: % and remove those bands from FTM, electrodes and crossover freq table tomwalters@0: toohigh=sum(crossover_freqs_greenwood>0.5*pre.resynthesis_rate); tomwalters@0: crossover_freqs_greenwood=crossover_freqs_greenwood(1:end-toohigh); % only those < half the sampling rate tomwalters@0: pre.electrodes=pre.electrodes(1:sum(p.electrodes>toohigh)); tomwalters@0: FTM=FTM(1:sum(p.electrodes>toohigh),:); tomwalters@0: num_bands_after=length(pre.electrodes); tomwalters@0: if pre.num_bands~=num_bands_after tomwalters@0: msgbox([num2str(pre.num_bands-num_bands_after) ' of the active basal electrodes correspond(s) to frequencies > half the sampling frequency and will be disabled.'],'Disabling electrodes','warn','modal'); tomwalters@0: end tomwalters@0: pre.num_bands=num_bands_after; tomwalters@0: tomwalters@0: % resynthesize tomwalters@0: % ------------ tomwalters@0: %sinusoid tomwalters@0: pre.resynthesis_carrier = 'sinus'; tomwalters@0: if get(handles.AnalRadio,'Value') tomwalters@0: pre.crossover_freqs=p.crossover_freqs; % sinusoids following crossover frequencies as in analysis tomwalters@0: filename=[filename '_sinus']; tomwalters@0: else tomwalters@0: pre.crossover_freqs=crossover_freqs_greenwood; % sinusoids following Greenwood tomwalters@0: filename=[filename '_sinus_green_' num2str(cochlength) '_' num2str(insertion)]; tomwalters@0: end tomwalters@0: else % NOISE tomwalters@0: pre.resynthesis_carrier = 'noise'; tomwalters@0: if get(handles.AnalRadio,'Value') tomwalters@0: pre.crossover_freqs=p.crossover_freqs; % noise bands following analysis freq bands, non-overlapping tomwalters@0: filename=[filename '_noise']; tomwalters@0: else tomwalters@0: if get(handles.OverBox,'Value') % exponentially decaying, overlapping frequency bands, after Greenwood tomwalters@0: for i=1:22 tomwalters@0: pre.resynthesis_A(i,:) = 1; tomwalters@0: pre.resynthesis_B(i,:) = CISimulationFilter(insertion-elecspacing*(i-1),pre.resynthesis_rate,b,cochlength); tomwalters@0: end tomwalters@0: filename=[filename '_noise_green_' num2str(cochlength) '_' num2str(insertion) '_olap_' num2str(b)]; tomwalters@0: else % crossover frequencies after Greenwood, non-overlapping tomwalters@0: pre.crossover_freqs=crossover_freqs_greenwood; tomwalters@0: filename=[filename '_noise_green_' num2str(cochlength) '_' num2str(insertion)]; tomwalters@0: end tomwalters@0: end tomwalters@0: end tomwalters@0: tomwalters@0: pre = resynthesis(pre); tomwalters@0: simul = resynthesis(pre,FTM); tomwalters@0: tomwalters@0: %Windowing and zeropadding to remove clicks tomwalters@0: w = risewindow(length(simul),0.01*pre.resynthesis_rate)'; %a 10 ms linear rise and fall tomwalters@0: simul = [zeros(1,10) w.*simul zeros(1,10)]; tomwalters@0: tomwalters@0: if get(handles.NormalizeBox,'Value') % normalize output tomwalters@0: amp1=sum(handles.audio.^2); tomwalters@0: amp2=sum(simul.^2); tomwalters@0: %simul=simul*sqrt(amp1/amp2); % normalize to input level tomwalters@0: simul=0.9*simul/max(abs(simul)); % normalize to 90 % tomwalters@0: end tomwalters@0: tomwalters@0: return;