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axi_dac_interpolate: Added matlab file for interpolation filters

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Adrian Costina 2017-07-21 14:37:27 +03:00
parent bf810bcc4b
commit afbce10ab9
1 changed files with 43 additions and 0 deletions
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library/axi_dac_interpolate/m2k_interp.m Normal file
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clear all;
close all;
interp_rate = 50000;
h_cic = dsp.CICInterpolator('InterpolationFactor', interp_rate, 'NumSections',6 );%, ...
%'FixedPointDataType','Specify word and fraction lengths', ...
%'SectionWordLengths', [12 20 28 35 43 51], ...
%'SectionFractionLengths', [11 11 11 11 11 11], ...
%'OutputWordLength', 12, ...
%'OutputFractionLength', 11);
gainCIC = (h_cic.InterpolationFactor*h_cic.DifferentialDelay)^h_cic.NumSections
[h1, w1] = h_cic.freqz();
fs = 1;
fPass = 0.20;
fStop = 0.50;
ast = 70;
prip = 0.05;
CICCompInterp = dsp.CICCompensationInterpolator(h_cic, ...
'InterpolationFactor',2,'PassbandFrequency',fPass, ...
'StopbandFrequency',fStop,'StopbandAttenuation',ast, ...
'SampleRate',fs);
[h2, w2] = CICCompInterp.freqz();
CICCompInterp.coeffs()
FC = dsp.FilterCascade(CICCompInterp, h_cic);
[h3, w3] = FC.freqz();
subplot(211); hold on;
plot(w1/pi, 20*log10(abs(h1)/gainCIC));
plot(w2/pi, 20*log10(abs(h2)));
hold off; grid
subplot(212); plot(w3/pi, 20*log10(abs(h3)/gainCIC/sum(CICCompInterp.coeffs().Numerator))); grid
nt = numerictype(1,16,15);
fdhdltool(CICCompInterp, nt);
nt = numerictype(1,36,30);
fdhdltool(h_cic,nt);