fftseq.m

绘出DSB解调器的输出并给出功率为其0.001

function[M,m,df]=fftseq(m,ts,df)
%       [M,m,df]=fftseq(m,ts,df)
%       [M,m,df]=fftseq(m,ts)
%FFTSEQ   Generates M,the FFT of the sequence m.
%       The sequence is zero padded to meet the required frequency
%       resolution df.
%       ts is the sampling interval.The output df is the final frequency
%       resolution.
%       Output m is the zero padded version of input m.M is the FFT.
fs=1/ts;
if nargin==2
    n1=0;
else
    n1=fs/df;
end
n2=length(m);
n=2^(max(nextpow2(n1),nextpow2(n2)));
M=fft(m,n);
m=[m,zeros(1,n-n2)];
df=fs/n;