Приложение 3

Программный код и результаты моделирования для тестового сигнала

%Исходные данные

Fs = 96e3;

f1 = 1.5e3;

f2 = 20e3;

f3 = 25e3;

dt = 1/Fs;

T1 = 1/f1;

t = 0: dt: T1*50;

df_shift = 10000;

S1 = (j*sin (2*pi*f1*t) + cos (2*pi*f1*t)) + (j*sin (2*pi*f2*t) + cos (2*pi*f2*t)) + (j*sin (2*pi*f3*t) + cos (2*pi*f3*t));

% shift to center frequnce for real filtering

S1 = S1. * exp (j*2*pi* (-df_shift) *t);

%Окно Хэмминга и построение спектра исходного сигнала

w = hamming (2048). ';

S2= [];

for i=1: floor (length (S1) /2048)

S2 = [S2 S1 ( (i-1) *2048+1: i*2048). *w];

end

Hs1=spectrum. periodogram;

figure (1)

h1 = psd (Hs1,S2,'Fs',Fs); plot (h1)

%Кан. Фильтр order = 122

%fs = 96000 fpass = 10000 fstop = 12000 astop = 80

S1 = [zeros (1,length (k0) - 1) S1];

r0 = zeros (1, length (S1));

for i = length (k0): length (S1)

for n = 0: length (k0) - 1

r0 (i) = r0 (i) + S1 (i-n) *k0 (n+1);

end

end

r0 (1: length (k0) - 1) = [];

hold on

h1 = psd (Hs1,r0,'Fs',Fs); plot (h1)

%фильтр перенос order = 33

%fs = 768000 fpass = 10000 fstop = 55000 astop = 60

B0 = upsample (r0,8);

B0 = [zeros (1,length (kn) - 1) B0];

r1 = zeros (1,length (B0));

for i = length (kn): length (B0)

for n = 0: length (kn) - 1

r1 (i) = r1 (i) +B0 (i-n) *kn (n+1);

end

end

r1 (1: length (kn) - 1) = [];

figure (2)

h1 = psd (Hs1,r1,'Fs',768000); plot (h1)

%Первый FiR-фильтр order = 8

%fs = 1536000 fpass = 10000 fstop = 384000 astop = 80

B = upsample (r1,2);

B = [zeros (1,length (k1) - 1) B];

r2 = zeros (1,length (B));

for i = length (k1): length (B)

for n = 0: length (k1) - 1

r2 (i) = r2 (i) +B (i-n) *k1 (n+1);

end

end

%Второй FiR-фильтр order =8

%fs = 3072000 fpass = 10000 fstop = 768000 astop = 80

B1 = upsample (r2,2);

B1 (1: length (k2) - 1) = [];

r3 = zeros (1,length (B1));

for i = length (k2): length (r3)

for n = 0: length (k2) - 1

r3 (i) = r3 (i) +B1 (i-n) *k2 (n+1);

end

end

r3 (1: length (k2) - 1) = [];

%CIC

D = 64; % filter buffer depth

B2 = upsample (r3, 32);

delayBuffer1 = zeros (1,D);

delayBuffer2 = zeros (1,D);

delayBuffer3 = zeros (1,D);

delayBuffer4 = zeros (1,D);

intOut1 = 0;

intOut2 = 0;

intOut3 = 0;

intOut4 = 0;

for ii = 1: (length (B2) /10

%comb1

combOut1 = B2 (ii) - delayBuffer1 (end);

delayBuffer1 (2: end) = delayBuffer1 (1: end-1);

delayBuffer1 (1) = B2 (ii);

% integrator1

intOut1 = intOut1 + combOut1;

r4 (ii) = intOut1;

%comb2

combOut2 = r4 (ii) - delayBuffer2 (end);

delayBuffer2 (2: end) = delayBuffer2 (1: end-1);

delayBuffer2 (1) = r4 (ii);

% integrator2

intOut2 = intOut1 + combOut2;

r5 (ii) = intOut2;

%comb3

combOut3 = r5 (ii) - delayBuffer3 (end);

delayBuffer3 (2: end) = delayBuffer3 (1: end-1);

delayBuffer3 (1) = r5 (ii);

% integrator3

intOut3 = intOut2 + combOut3;

r6 (ii) = intOut3;

%comb4

combOut4 = r6 (ii) - delayBuffer4 (end);

delayBuffer4 (2: end) = delayBuffer4 (1: end-1);

delayBuffer4 (1) = r6 (ii);

% integrator3

intOut4 = intOut3 + combOut4;

r7 (ii) = intOut4;

end

%Спектр выходного сигнала

figure (3)

h1 = psd (Hs1,r7,'Fs',98304000); plot (h1)

title ('Power Spectrum of a Sine Wave'); % Вывод названия графика.

xlabel ('Frequency (Hz) '); % Вывод величины и размерности по x.

ylabel ('Power'); % Вывод величины по y.

Спектр исходного сигнала (рис. 19).

Рис. 19

Спектр сигнала после всех фильтров (рис. 20)

Рис. 20

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