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Tools: Tune: Add frequency response and group delay plots 

The plots help to understand beamformer channel filters characteristic.
Frequency response is usually all-pass type and group delays match
the delays need to time-align the waveforms from steer angle.

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
This commit is contained in:
Seppo Ingalsuo 2020-12-21 18:39:48 +02:00 committed by Liam Girdwood
parent 064285e19c
commit 53c7ea6dd1
1 changed files with 51 additions and 4 deletions
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55
tools/tune/tdfb/bf_design.m
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@ -231,16 +231,44 @@ if bf.do_plots
grid on;
xlabel('FIR coefficient'); ylabel('Tap value');
title(['FIR filters ' bf.array_id], 'Interpreter','none');
ch_legend(bf.num_filters);
%% Frequency responses
fh(3) = figure(bf.fn + 2);
f = linspace(0, bf.fs/2, 256);
h = zeros(256, bf.num_filters);
for i = 1:bf.num_filters
h(:,i) = freqz(bf.w(:,i), 1, f, bf.fs);
end
plot(f, 20*log10(abs(h)));
grid on
ylabel('Magnitude (dB)');
xlabel('Frequency (Hz)');
title(['FIR magnitude responses ' bf.array_id], 'Interpreter','none');
ch_legend(bf.num_filters);
%% Group delays
fh(4) = figure(bf.fn + 3);
gd = zeros(256, bf.num_filters);
for i = 1:bf.num_filters
gd(:,i) = grpdelay(bf.w(:,i), 1, f, bf.fs);
end
plot(f, gd/bf.fs*1e6);
grid on
ylabel('Group delay (us)');
xlabel('Frequency (Hz)');
title(['FIR group delays ' bf.array_id], 'Interpreter','none');
ch_legend(bf.num_filters);
%% DI
bf.fh(3) = figure(bf.fn + 2);
bf.fh(5) = figure(bf.fn + 4);
semilogx(bf.f(2:end), bf.di_db(2:end))
xlabel('Frequency (Hz)'); ylabel('DI (dB)'); grid on;
legend('Suppression of diffuse field noise','Location','SouthEast');
title(['Directivity Index ' bf.array_id], 'Interpreter','none');
%% WNG
bf.fh(4) = figure(bf.fn + 3);
bf.fh(6) = figure(bf.fn + 5);
semilogx(bf.f(2:end), bf.wng_db(2:end))
xlabel('Frequency (Hz)'); ylabel('WNG (dB)'); grid on;
legend('Attenuation of uncorrelated noise','Location','SouthEast');
@ -248,7 +276,7 @@ if bf.do_plots
drawnow;
%% 2D
bf.fh(5) = figure(bf.fn + 4);
bf.fh(7) = figure(bf.fn + 6);
colormap(jet);
phi_deg = phi_rad*180/pi;
imagesc(bf.f, bf.resp_angle, 20*log10(abs(bf.resp_fa)), [-30 0]);
@ -259,7 +287,7 @@ if bf.do_plots
title(['Spatial response ' bf.array_id], 'Interpreter','none');
%% Polar
bf.fh(6) = figure(bf.fn + 5);
bf.fh(8) = figure(bf.fn + 7);
flist = [1000 2000 3000 4000];
idx = [];
for i = 1:length(flist)
@ -394,3 +422,22 @@ end
dt = dm/bf.c;
end
function ch_legend(n)
switch n
case 2
legend('1', '2');
case 3
legend('1', '2', '3');
case 4
legend('1', '2', '3', '4');
case 5
legend('1', '2', '3', '4', '5');
case 6
legend('1', '2', '3', '4', '5', '6');
case 7
legend('1', '2', '3', '4', '5', '6', '7');
otherwise
legend('1', '2', '3', '4', '5', '6', '7', '8');
end
end