[matlab] general function of communication signal modulation bandpass filter

Catalog

Bandpass filter

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Bandpass filter

function [t,st] = bpf(f,sf,B1,B2)
%This function filter an input at frequency domain by an ideal bandpass filter
%Inputs:
% f: frequency samples
% sf: input data spectrum samples
% B1: bandpass's lower frequency
% B2: bandpass's higher frequency
%Outputs:
% t: time samples
% st: output data's time samples
df = f(2)-f(1);
T = 1/df;
hf = zeros(1,length(f));
bf = [floor(B1/df ): floor(B2/df)] ;
bf1 = floor(length(f)/2) + bf;
bf2 = floor(length(f)/2) - bf;
hf(bf1)=1;
hf(bf2)=1;
yf = hf.*sf;
[t,st] = F2T(f,yf);
st = real(st);