bpf.m

来自「这是基于MATLAB的数字调相技术编程,包括对调制解调过程的编程以及其有效性和可」· M 代码 · 共 22 行

function[t,st]=bpf(f,sf,B1,B2)
%This function filter an input at frequency domain by an ideal
%bandpass filter
%input:
%    f:frequency samples
%    sf:input data spectrun samples
%    B1:bandpass's lower frequency
%    B2:bandpass's higher frequency
%Output:
%    t:frequency 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/sqrt(2*(B2-B1));
hf(bf2)=1/sqrt(2*(B2-B1));

yf=hf.*sf.*exp(-j*2*pi*f*0.1*T);
[t,st]=F2T(f,yf);