log_psd.m

通信与系统仿真原理与无线应用第五章附录例5-11

%File:log_psd.m

function [logpsd,freq,ptotal,pmax]=log_psd(x,n,ts)
%
%
y=zeros(1,n);
%
h=waitbar(0,'For loop in PSD Calculation');
for k=1:n
    freq(k)=(k-1-(n/2))/(n*ts);
    y(k)=x(k)*((-1.0)^k);
    waitbar(k/n)
end;
%
v=fft(y)/n;
psd=abs(v).^2;
pmax=max(psd);
ptotal=sum(psd);
logpsd=10*log10(psd/pmax);
%
%
for k=1:n
    if(logpsd(k)<-60.0)
        logpsd(k)=-60.0;
    end
end
close(h)

%End of function file.