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- added CIC-decimator

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git-svn-id: http://moon:8086/svn/vhdl/trunk@156 cc03376c-175c-47c8-b038-4cd826a8556b
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jens
2008-12-28 16:30:56 +00:00
parent 28bd8e959d
commit 1e9bed13e5
1 changed files with 34 additions and 2 deletions
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lib/radio/nco/sim/tb_mix_results.m
+34 -2
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@@ -2,12 +2,16 @@
function tb_mix_results()
fa = 100.0;
f = TEXTREAD('freq.txt')*1E-6
R = 128;
fa_dec = fa/R
N_pfir = 63;
I_in = TEXTREAD('i_in.txt')';
I_out = TEXTREAD('i_out.txt')';
Q_out = TEXTREAD('q_out.txt')';
N= length(I_out);
N_fft = N
N= length(I_out)
N_fft = N;
N_fft2 = N_fft/2;
fft_y2 = 2/N_fft*abs(fft(I_out(1:N_fft).*hann(N_fft)'));
@@ -22,9 +26,35 @@ fft_y3 = 2/N_fft*abs(fft(I_in(1:N_fft).*hann(N_fft)'));
max_ditherd_spur_freq = (i*fa/N_fft);
max_ditherd_spur_value = 20*log10(v);
I_out_dec = cic_filter(R, 1, 3, I_out);
Q_out_dec = cic_filter(R, 1, 3, Q_out);
N_dec = length(I_out_dec)-2*N_pfir;
N_fft_dec = N_dec
N_fft2_dec = N_fft_dec/2;
fft_y2_dec = 2/N_fft_dec*abs(fft(I_out_dec(2*N_pfir+1:N_fft_dec+2*N_pfir).*hann(N_fft_dec)'));
pfir_b = sinc(0.1*(-(N_pfir-1)/2:1:(N_pfir)/2));
pfir_b = pfir_b/sum(pfir_b).*blackman(N_pfir)';
I_out_dec_pfir = filter(pfir_b, 1, I_out_dec);
Q_out_dec_pfir = filter(pfir_b, 1, Q_out_dec);
fft_y2_dec_pfir = 2/N_fft_dec*abs(fft(I_out_dec_pfir(2*N_pfir+1:N_fft_dec+2*N_pfir).*hann(N_fft_dec)'));
% Output
close all;
plot(fa/(R*N_fft_dec)*(0:N_fft2_dec),20*log10(fft_y2_dec(1:N_fft2_dec+1)), '-', fa/(R*N_fft_dec)*(0:N_fft2_dec),20*log10(fft_y2_dec_pfir(1:N_fft2_dec+1)), '-'); grid;
figure;
plot(1:length(I_out_dec_pfir), I_out_dec_pfir, 1:length(Q_out_dec_pfir), Q_out_dec_pfir); grid;
figure;
freqz(pfir_b, 1, 1000);
figure;
plot(pfir_b); grid;
figure;
subplot(2,1,1)
plot(fa/N_fft*(0:N_fft2),20*log10(fft_y2(1:N_fft2+1)), '-', fa/N_fft*(0:N_fft2), max_spur_value*ones(1,N_fft2+1), 'r-', [max_spur_freq], [max_spur_value], 'ro'); grid;
spur_legend = sprintf('Max. spur %.1fdB at %.3fMHz', max_spur_value, max_spur_freq);
@@ -43,6 +73,8 @@ ylabel('dB');
xlabel('f/MHz');
axis([0 fa/2 -140 0]);
plot(1:N, I_out, 1:N, Q_out); grid;
function [max_i, max_v] = get_maxpur(spec, fa, f)
max_v = 0;
max_i = 0;