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DEMO_GAMMATONE
Demo for gammatone.m
Program code:
% DEMO_GAMMATONE Demo for gammatone.m
%
% DEMO_GAMMATONE demonstrates the usage of various Gammatone filter
% implementations in the AMT.
%
% Figure 1: Gammatone IRs obtained with the `gammatone` implementation with the option classic (Patterson et al., 1987).
%
% This figure shows IRs of Gammatone filters in 24 erb-spaced channels
% derived from gammatone with parameters classic and real (Patterson et al., 1987).
% Left panel shows the causalphase option. Right panel shows the
% peakphase option, which aligns the IRs to the maxima of the corresponding
% envelope maxima.
%
% Figure 2: Gammatone IRs obtained with the `gammatone` implementation with the option complex (Hohmann, 2002).
%
% This figure shows IRs of Gammatone filters in 24 erb-spaced channels
% derived from gammatone with parameters allpole and complex (Hohmann,
% 2002). Left panel shows the causalphase option. Right panel shows the
% peakphase option, which aligns the IRs to the maxima of the corresponding
% envelope maxima.
%
% Figure 3: Gammatone IRs obtained with `hohmann2002` corresponding to complex-valued allpole filters (Hohmann, 2002).
%
% This figure shows IRs of Gammatone filters in 24 erb-spaced channels
% derived with hohmann2002 . This
% implementation corresponds to complex-valued allpole Gammatone filters
% (Hohmann, 2002). Left panel shows the IRs as output by
% hohmann2002_process, the right panel shows those IRs manually delayed
% such that their maxima are aligned across frequency channels.
%
%
% See also: exp_gammatone gammatone exp_hohmann2002 demo_hohmann2002 hohmann2002
%
% Url: http://amtoolbox.org/amt-1.6.0/doc/demos/demo_gammatone.php
% #Author: Christian Klemenschitz (2014)
% This file is licensed unter the GNU General Public License (GPL) either
% version 3 of the license, or any later version as published by the Free Software
% Foundation. Details of the GPLv3 can be found in the AMT directory "licences" and
% at <https://www.gnu.org/licenses/gpl-3.0.html>.
% You can redistribute this file and/or modify it under the terms of the GPLv3.
% This file is distributed without any warranty; without even the implied warranty
% of merchantability or fitness for a particular purpose.
%% Figure gammatone, classic, Real
% Parameters;
flow = 100; % Lowest center frequency in Hz;
fhigh = 4000; % Highest center frequency in Hz;
fs = 28000; % Sampling rate in Hz;
fc = erbspacebw(flow,fhigh); % 24 erb-spaced channels;
nchannels = length(fc); % Number of channels;
N = 8192; % Number of samples;
insig = [1, zeros(1,8191)]; % Impulse signal;
treal = (1:N)/fs*1000; % Time axis;
%---- classic real ----
% Derive filter coefficients and filter impulse responses;
[b,a] = gammatone(fc,fs,'classic','causalphase','real');
outsig1 = 2*real(ufilterbankz(b,a,insig));
outsig1 = permute(outsig1,[3 2 1]);
% Derive filter coefficients and filter impulse responses with option 'peakphase';
[b,a] = gammatone(fc,fs,'classic','peakphase','real');
outsig2 = 2*real(ufilterbankz(b,a,insig));
outsig2 = permute(outsig2,[3 2 1]);
% Figure 1;
type1 = 'classic / causalphase / real'; % Type of implemantion for headline;
type2 = 'classic / peakphase / real'; % Type of implemantion for headline;
% Plot
% Figure 1 - classic real;
figure('units','normalized','outerposition',[0 0.525 1 0.475]);
set(gcf,'Name','gammatone, classic, real');
subplot(1,2,1)
hold on
dy = 1;
for ii = 1:nchannels
plot(treal,40*real(outsig1(ii,:)) + dy)
dy = dy + 1;
end
% clear dy;
title (['Gammatone impulse responses of type: ', num2str(type1)])
xlabel 'Time (ms)'
ylabel ([ num2str(nchannels),' channels / ', num2str(flow), ' - ',num2str(fhigh),' Hz'])
ylabel('# Frequency Channel (ERB): Frequency (Hz)');
xt = 0:5:25;
yt = [1 4 8 12 16 20 24];
axis([0, 25, 0, 26]);
set(gca,'XTick',xt, 'YTick', yt)
set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
['#24: ' num2str(round(fc(24))) ' Hz']})
box on
hold off
print(gcf,'-dpng','Gammatone')
subplot(1,2,2)
hold on
dy = 1;
for ii = 1:nchannels
plot(treal,40*real(outsig2(ii,:)) + dy)
dy = dy + 1;
end
% clear dy;
title (['Gammatone impulse responses of type: ', num2str(type2)])
xlabel 'Time (ms)'
ylabel('# Frequency Channel (ERB): Frequency (Hz)');
xt = 0:5:25;
yt = [1 4 8 12 16 20 24];
axis([0, 25, 0, 26]);
set(gca,'XTick',xt, 'YTick', yt)
set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
['#24: ' num2str(round(fc(24))) ' Hz']})
box on
hold off
%% Figure gammatone, classic, complex: This parameter configuration does not work and should be avoided
% .. figure::
%
% Classic gammatone implementation with complex-valued filter coefficients derived from gammatone.m.
%
% This figure shows in the first plot an array of 24 erb-spaced channels of
% classic gammatone implementation (Patterson et al., 1987) derived from
% gammatone.m with complex-valued filter coefficients and in the second
% plot this implementation with option 'peakphase', which makes the phase
% of each filter be zero when the envelope of the impulse response of the
% filter peaks (both do not scale correctly).
%
% % Parameters;
% flow = 100; % Lowest center frequency in Hz;
% fhigh = 4000; % Highest center frequency in Hz;
% fs = 28000; % Sampling rate in Hz;
% fc = erbspacebw(flow,fhigh); % 24 erb-spaced channels;
% nchannels = length(fc); % Number of channels;
% N = 8192; % Number of samples;
% insig = [1, zeros(1,8191)]; % Impulse signal;
% treal = (1:N)/fs*1000; % Time axis;
%
% %---- classic complex ----
% amt_disp('Classic, complex-valued, causal-phased gammtone implementation:');
% % Derive filter coefficients and filter impulse responses;
% [b,a] = gammatone(fc,fs,'classic','causalphase','complex');
% outsig1 = 2*real(ufilterbankz(b,a,insig));
% outsig1 = permute(outsig1,[3 2 1]);
%
% amt_disp('Classic, complex-valued, peak-phased gammtone implementation:');
% % Derive filter coefficients and filter impulse responses with option 'peakphase';
% [b,a] = gammatone(fc,fs,'classic','peakphase','complex');
% outsig2 = 2*real(ufilterbankz(b,a,insig));
% outsig2 = permute(outsig2,[3 2 1]);
%
% % Figure 2;
% type1 = 'classic / causalphased / complex'; % Type of implemantion for headline;
% type2 = 'classic / peakphased / complex'; % Type of implemantion for headline;
%
% % Plot
% % Figure 2 - classic complex;
% figure('units','normalized','outerposition',[0 0.05 1 0.475])
% set(gcf,'Name','gammatone, classic, complex');
% subplot(1,2,1)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,40*real(outsig1(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type1)])
% xlabel 'Time (ms)'
% ylabel ([ num2str(nchannels),' channels / ', num2str(flow), ' - ',num2str(fhigh),' Hz'])
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, 0, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
% subplot(1,2,2)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,40*real(outsig2(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type2)])
% xlabel 'Time (ms)'
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, 0, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%% Figure gammatone, allpole, complex
% Parameters;
flow = 100; % Lowest center frequency in Hz;
fhigh = 4000; % Highest center frequency in Hz;
fs = 28000; % Sampling rate in Hz;
fc = erbspacebw(flow,fhigh); % 24 erb-spaced channels;
nchannels = length(fc); % Number of channels;
N = 8192; % Number of samples;
insig = [1, zeros(1,8191)]; % Impulse signal;
treal = (1:N)/fs*1000; % Time axis;
%---- allpole complex ----
% Derive filter coefficients and filter impulse responses;
[b,a] = gammatone(fc,fs,'allpole','causalphase','complex');
outsig1 = 2*real(ufilterbankz(b,a,insig));
outsig1 = permute(outsig1,[3 2 1]);
% Derive filter coefficients and filter impulse responses with option 'peakphase';
[b,a] = gammatone(fc,fs,'allpole','peakphase','complex');
outsig2 = 2*real(ufilterbankz(b,a,insig));
outsig2 = permute(outsig2,[3 2 1]);
% Figure 3;
type1 = 'allpole / causalphase / complex'; % Type of implemantion for headline;
type2 = 'allpole / peakphase / complex'; % Type of implemantion for headline;
% Plot
% Figure 3 - allpole complex;
figure('units','normalized','outerposition',[0 0.05 1 0.475]);
set(gcf,'Name','gammatone, allpole, complex');
subplot(1,2,1)
hold on
dy = 1;
for ii = 1:nchannels
plot(treal,40*real(outsig1(ii,:)) + dy)
dy = dy + 1;
end
% clear dy;
title (['Gammatone impulse responses of type: ', num2str(type1)])
xlabel 'Time (ms)'
ylabel ([ num2str(nchannels),' channels / ', num2str(flow), ' - ',num2str(fhigh),' Hz'])
ylabel('# Frequency Channel (ERB): Frequency (Hz)');
xt = 0:5:25;
yt = [1 4 8 12 16 20 24];
axis([0, 25, 0, 26]);
set(gca,'XTick',xt, 'YTick', yt)
set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
['#24: ' num2str(round(fc(24))) ' Hz']})
box on
hold off
subplot(1,2,2)
hold on
dy = 1;
for ii = 1:nchannels
plot(treal,40*real(outsig2(ii,:)) + dy)
dy = dy + 1;
end
% clear dy;
title (['Gammatone impulse responses of type: ', num2str(type2)])
xlabel 'Time (ms)'
ylabel('# Frequency Channel (ERB): Frequency (Hz)');
xt = 0:5:25;
yt = [1 4 8 12 16 20 24];
axis([0, 25, 0, 26]);
set(gca,'XTick',xt, 'YTick', yt)
set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
['#24: ' num2str(round(fc(24))) ' Hz']})
box on
hold off
%% Figure hohmann2002 implementation
% Hohmann implementation;
% Parameters;
fs = 28000; % Sampling rate in Hz;
flow = 100; % Lowest center frequency in Hz;
basef = 888.44; % Base center frequency in Hz;
fhigh = 4000; % Highest center frequency in Hz;
filters_per_ERBaud = 1; % Filterband density on ERB scale;
% Construct new analyzer object;
analyzer = hohmann2002(fs,flow, basef, fhigh,filters_per_ERBaud);
% Impulse signal;
impulse = [1; zeros(8191,1)];
% Filter signal;
[impulse_response, analyzer] = hohmann2002_process(analyzer, impulse);
% impulse_response = impulse_response'; % work around because dim#1 is time
% Find peak at envelope maximum for lowest channel and add one sample;
delay_samples = find(abs(impulse_response(:,1)) == max(abs(impulse_response(:,1)))) + 1;
%
delay = hohmann2002_delay(analyzer, delay_samples);
[outsig, delay] = hohmann2002_process(delay, impulse_response);
% outsig=outsig'; % work around because dim#1 is time
% Figure 4;
type1 = 'plotted as they are'; % Type of implemantion for headline;
type2 = 'manually delayed to align their max'; % Type of implemantion for headline;
% Plot
% Figure 4 - hohmann2002 implementation, corresponds to allpole complex;
figure ('units','normalized','outerposition',[0 0.05 1 0.475])
set(gcf,'Name','hohmann2002');
subplot(1,2,1)
hold on
dy = 1;
for ii = 1:nchannels
plot(treal,40*real(impulse_response(:,ii)) + dy)
dy = dy + 1;
end
% clear dy;
title (['Impulse responses (IRs) from hohmann2002\_process: ', num2str(type1)])
xlabel 'Time (ms)'
ylabel('# Frequency Channel (ERB): Frequency (Hz)');
xt = 0:5:25;
yt = [1 4 8 12 16 20 24];
axis([0, 25, 0, 26]);
set(gca,'XTick',xt, 'YTick', yt)
set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
['#24: ' num2str(round(fc(24))) ' Hz']})
box on
hold off
subplot(1,2,2)
hold on
dy = 1;
for ii = 1:nchannels
plot(treal,40*real(outsig(:,ii)) + dy)
dy = dy + 1;
end
% clear dy;
title (['IRs from hohmann2002: ', num2str(type2)])
xlabel 'Time (ms)'
ylabel('# Frequency Channel (ERB): Frequency (Hz)');
xt = 0:5:25;
yt = [1 4 8 12 16 20 24];
axis([0, 25, 0, 26]);
set(gca,'XTick',xt, 'YTick', yt)
set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
['#24: ' num2str(round(fc(24))) ' Hz']})
box on
hold off
%% Figure, gammatone classic, real, but with 6dbperoctave
% .. figure::
%
% Classic gammatone implementation with real-valued filter coefficients derived from gammatone.m with otpion '6dBperoctave'.
%
% Figure 5 shows in the first plot an array of 24 erb-spaced channels of
% classic gammatone implementation (Patterson et al., 1987) with real-valued
% filter coefficients and option '6dBperoctave', which scales the amplitude
% +/- 6 dB per octave with 0 dB at 4000 Hz and in the second plot this
% implementation with option 'exppeakphase', which makes the phase of each
% filter be zero when the envelope of the impulse response of the filter peaks.
% % Parameters;
% flow = 100; % Lowest center frequency in Hz;
% fhigh = 4000; % Highest center frequency in Hz;
% fs = 28000; % Sampling rate in Hz;
% fc = erbspacebw(flow,fhigh); % 24 erb-spaced channels;
% nchannels = length(fc); % Number of channels;
% N = 8192; % Number of samples;
% insig = [1, zeros(1,8191)]; % Impulse signal;
% treal = (1:N)/fs*1000; % Time axis;
%
%
% %---- classic real 6dBperoctave ----
% % Derive filter coefficients and filter impulse responses with option '6dBperoctave';
% [b,a] = gammatone(fc,fs,'classic','real','6dBperoctave');
% outsig1 = 2*real(ufilterbankz(b,a,insig));
% outsig1 = permute(outsig1,[3 2 1]);
%
% %---- classic real peakphase(new) 6dBperoctave ----
% % Derive filter coefficients and filter impulse responses with option '6dBperoctave';
% [b,a] = gammatone(fc,fs,'classic','real','exppeakphase','6dBperoctave');
% outsig2 = 2*real(ufilterbankz(b,a,insig));
% outsig2 = permute(outsig2,[3 2 1]);
%
% % Figure 5;
% type1 = 'classic / casualphased / real / +/-6dB'; % Type of implemantion for headline;
% type2 = 'classic / peakphased(new) / real / +/-6dB'; % Type of implemantion for headline;
%
% % Plot
% % Figure 5 - classic / causalphased / real / +/-6dB;
% figure('units','normalized','outerposition',[0 0.525 1 0.475])
% subplot(1,2,1)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,8*real(outsig1(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type1)])
% xlabel 'Time (ms)'
% ylabel ([ num2str(nchannels),' channels / ', num2str(flow), ' - ',num2str(fhigh),' Hz'])
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, -4, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
% subplot(1,2,2)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,8*real(outsig2(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type2)])
% xlabel 'Time (ms)'
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, -4, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
%% Figure gammatone allpole, complex, but with 6dbperoctave
% .. figure::
%
% Allpole gammatone implementation with real-valued filter coefficients derived from gammatone.m with otpion '6dBperoctave'.
%
% Figure 6 shows in the first plot an array of 24 erb-spaced channels of
% allpole gammatone implementation (Hohmann, 2002) with complex-valued
% filter coefficients and option '6dBperoctave', which scales the amplitude
% +/- 6 dB per octave with 0 dB at 4000 Hz and in the second plot this
% implementation with option 'exppeakphase', which makes the phase of each
% filter be zero when the envelope of the impulse response of the filter peaks.
%
% % Parameters;
% flow = 100; % Lowest center frequency in Hz;
% fhigh = 4000; % Highest center frequency in Hz;
% fs = 28000; % Sampling rate in Hz;
% fc = erbspacebw(flow,fhigh); % 24 erb-spaced channels;
% nchannels = length(fc); % Number of channels;
% N = 8192; % Number of samples;
% insig = [1, zeros(1,8191)]; % Impulse signal;
% treal = (1:N)/fs*1000; % Time axis;
%
% %---- allpole complex 6dBperoctave ----
% % Derive filter coefficients and filter impulse responses with option '6dBperoctave';
% [b,a] = gammatone(fc,fs,'allpole','complex','6dBperoctave');
% outsig1 = 2*real(ufilterbankz(b,a,insig));
% outsig1 = permute(outsig1,[3 2 1]);
%
% %---- allpole peakphase(new) complex 6dBperoctave ----
% % Derive filter coefficients and filter impulse responses with option '6dBperoctave';
% [b,a] = gammatone(fc,fs,'allpole','complex','exppeakphase','6dBperoctave');
% outsig2 = 2*real(ufilterbankz(b,a,insig));
% outsig2 = permute(outsig2,[3 2 1]);
%
% % Figure 6;
% type1 = 'allpole / causalphased / complex / +/-6dB'; % Type of implemantion for headline;
% type2 = 'allpole / peakphased(new) / complex / +/-6dB'; % Type of implemantion for headline;
%
% % Plot
% % Figure 6 - classic / causalphased / real / +/-6dB;
% figure('units','normalized','outerposition',[0 0.05 1 0.475])
% subplot(1,2,1)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,8*real(outsig1(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type1)])
% xlabel 'Time (ms)'
% ylabel ([ num2str(nchannels),' channels / ', num2str(flow), ' - ',num2str(fhigh),' Hz'])
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, -2, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
% subplot(1,2,2)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,8*real(outsig2(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type2)])
% xlabel 'Time (ms)'
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, -2, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
%% Figure demo of manual delay
% .. figure::
%
% Classic with real-valued and allpole with complex-valued filter coefficients of gammatone implementation with otpion '6dBperoctave', peakphased and delayed.
%
% Figure 7 shows in the first plot an array of 24 erb-spaced channels of
% classic gammatone implementation (Patterson et al., 1987) with real-valued
% filter coefficients and option '6dBperoctave', which scales the amplitude
% +/- 6 dB per octave with 0 dB at 4000 Hz and option 'exppeakphase', which
% makes the phase of each filter be zero when the envelope of the impulse
% response of the filter peaks. Further the filters are delayed so the peaks
% of each filter are arranged above each other. The second plot shows the
% same but with allpole implementation (Hohmann, 2002) with complex-valued
% filter coefficients derived from gammatone.m.
%
% % Parameters;
% flow = 100; % Lowest center frequency in Hz;
% fhigh = 4000; % Highest center frequency in Hz;
% fs = 28000; % Sampling rate in Hz;
% fc = erbspacebw(flow,fhigh); % 24 erb-spaced channels;
% nchannels = length(fc); % Number of channels;
% N = 8192; % Number of samples;
% insig = [1, zeros(1,8191)]; % Impulse signal;
% treal = (1:N)/fs*1000; % Time axis;
%
% %---- classic real 6dBperoctave peakphased and delayed ----
% % Derive filter coefficients and filter impulse responses with option '6dBperoctave';
% [b,a] = gammatone(fc,fs,'classic','real','exppeakphase','6dBperoctave');
% outsig1 = 2*real(ufilterbankz(b,a,insig));
% outsig1 = permute(outsig1,[3 2 1]);
%
% % Find peak at maximum
% envmax1 = zeros(1,nchannels);
% for ii = 1:nchannels
% % maximum per channel
% envmax1(ii) = find(abs(outsig1(ii,:)) == max(abs(outsig1(ii,:))));
% end;
%
% % Delay signal
% for ii = 1:nchannels
% % Time to delay
% delay = zeros(1,max(envmax1)+1 - envmax1(ii));
% % Add delay
% outsig1(ii,:) = [delay outsig1(ii,1:N - length(delay))];
% end;
%
% % Type of implemantion for headline;
% type1 = 'classic / exppeakphased / real / 6dbperoctave / manually delayed';
%
% % Plot
% figure ('units','normalized','outerposition',[0 0.05 1 0.475])
% subplot(1,2,1)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,8*real(outsig1(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type1)])
% xlabel 'Time (ms)'
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, -4, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
% %---- allpole complex 6dBperoctave peakphased and delayed ----
% % Derive filter coefficients and filter impulse responses with option '6dBperoctave';
% [b,a] = gammatone(fc,fs,'allpole','complex','exppeakphase','6dBperoctave');
% outsig2 = 2*real(ufilterbankz(b,a,insig));
% outsig2 = permute(outsig2,[3 2 1]);
%
% % Find peak at envelope maximum
% envmax2 = zeros(1,nchannels);
% for ii = 1:nchannels
% % Envelope maximum per channel
% envmax2(ii) = find(abs(outsig2(ii,:)) == max(abs(outsig2(ii,:))));
% end;
%
% % Delay signal
% for ii = 1:nchannels
% % Time to delay
% delay = zeros(1,max(envmax2)+1 - envmax2(ii));
% % Add delay
% outsig2(ii,:) = [delay outsig2(ii,1:N - length(delay))];
% end;
%
% % Type of implemantion for headline;
% type2 = 'allpole / peakphased(new) / complex / +/-6dB / delayed';
%
% % Plot;
% subplot(1,2,2)
% hold on
% dy = 1;
% for ii = 1:nchannels
% plot(treal,8*real(outsig2(ii,:)) + dy)
% dy = dy + 1;
% end;
% clear dy;
% title (['Gammatone impulse responses of type: ', num2str(type2)])
% xlabel 'Time (ms)'
% ylabel('# Frequency Channel (ERB): Frequency (Hz)');
% xt = 0:5:25;
% yt = [1 4 8 12 16 20 24];
% axis([0, 25, -4, 26]);
% set(gca,'XTick',xt, 'YTick', yt)
% set(gca,'YTickLabel', {['#01: ' num2str(round(fc(1))) ' Hz'] , ['#04: ' num2str(round(fc(4))) ' Hz'], ...
% ['#08: ' num2str(round(fc(8))) ' Hz'], ['#12: ' num2str(round(fc(12))),' Hz'], ...
% ['#16: ' num2str(round(fc(16))),' Hz'], ['#20: ' num2str(round(fc(20))) ' Hz'], ...
% ['#24: ' num2str(round(fc(24))) ' Hz']})
% box on
% hold off
%
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