1 files changed, 32 insertions, 0 deletions
diff --git a/src/modules/audio_processing/agc/main/matlab/getGains.m b/src/modules/audio_processing/agc/main/matlab/getGains.m
new file mode 100644
index 0000000..e0234b8
--- /dev/null
+++ b/src/modules/audio_processing/agc/main/matlab/getGains.m
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+% Outputs a file for testing purposes. 
+%
+% Adjust the following parameters to suit. Their purpose becomes more clear on
+% viewing the gain plots.
+% MaxGain: Max gain in dB
+% MinGain: Min gain at overload (0 dBov) in dB
+% CompRatio: Compression ratio, essentially determines the slope of the gain
+%            function between the max and min gains
+% Knee: The smoothness of the transition to max gain (smaller is smoother)
+MaxGain = 5; MinGain = 0; CompRatio = 3; Knee = 1;
+
+% Compute gains
+zeros = 0:31; lvl = 2.^(1-zeros); 
+A = -10*log10(lvl) * (CompRatio - 1) / CompRatio;
+B = MaxGain - MinGain;
+gains = round(2^16*10.^(0.05 * (MinGain + B * ( log(exp(-Knee*A)+exp(-Knee*B)) - log(1+exp(-Knee*B)) ) / log(1/(1+exp(Knee*B))))));
+fprintf(1, '\t%i, %i, %i, %i,\n', gains);
+
+% Save gains to file
+fid = fopen('gains', 'wb');
+if fid == -1
+	error(sprintf('Unable to open file %s', filename));
+	return
+end
+fwrite(fid, gains, 'int32');
+fclose(fid);
+
+% Plotting
+in = 10*log10(lvl); out = 20*log10(gains/65536);
+subplot(121); plot(in, out); axis([-60, 0, -5, 30]); grid on; xlabel('Input (dB)'); ylabel('Gain (dB)');
+subplot(122); plot(in, in+out); axis([-60, 0, -60, 10]); grid on; xlabel('Input (dB)'); ylabel('Output (dB)');
+zoom on;