1 files changed, 51 insertions, 0 deletions
diff --git a/octave/doppler_spread_ut.m b/octave/doppler_spread_ut.m
new file mode 100644
index 0000000..f7d96b0
--- /dev/null
+++ b/octave/doppler_spread_ut.m
@@ -0,0 +1,51 @@
+% doppler_spread_ut.m
+% David Rowe Jan 2016
+%
+% Unit test script for doppler_spread
+
+f = 1;
+Fs = 8000;
+N  = Fs*10;
+
+[spread states] = doppler_spread(f, Fs, N);
+
+% use spreading samples to modulate 1000Hz sine wave
+% You can listen to this with: sine1k_1Hz.raw
+
+%   $ play -t raw -r 8000 -s -2 
+s = cos(2*pi*(1:N)*1000/Fs);
+s = s .* spread;
+s = real(s)*5000;
+fs = fopen("sine1k_1Hz.raw","wb"); fwrite(fs,s,"short"); fclose(fs);
+
+% Some plots
+
+x = states.x; y = states.y; b = states.b;
+
+H = freqz(b,1,x);
+
+figure(1)
+clf
+subplot(211)
+plot(x,y,';target;')
+title('Gaussian Filter Freq Resp Lin');
+legend('boxoff');
+subplot(212)
+plot(x,20*log10(y),';target;')
+hold on;
+plot(x,20*log10(y),'g+;actual;')
+hold off;
+axis([0 f*10/2 -60 0])
+title('Gaussian Filter Freq Resp dB');
+xlabel('Freq (Hz)');
+legend('boxoff');
+
+figure(2);
+subplot(211)
+plot(abs(spread))
+title('Spreading Function Magnitude');
+subplot(212)
+plot(s)
+title('1000Hz Sine Wave');
+xlabel('Time (samples)')
+