function?[alpha0alpha_profile]=fam（FsdfX）

%Sx=fam（FsdfdalphaNpLPNX）;

%?computes?spectral?auto?correlation?（SCD）?of?Signal?X

%?X?input
%?Fs?sampling?frequency
%?df?Desired?frequency?resolution
%?dalpha?Desired?cyclic?frequency?resolution

%?SX?output
%?alpha?Cyclic?Frequency
%?fo?Spectrum?Frequency

%-------------ver?description-------------%
%?input?SSB?modulation?also?added.
%-----------------------------------------%



%?clear?all;clc;?close?all;
%?load?lp_512Hz_fs8192Hz.dat;
%?Fs=8192;
%?df=256;
%?dalpha=64;
Np=pow2（nextpow2（Fs/df））;
L=Np/4;?%?This?should?be?chosen?to?be?less?than?or?equal?to?Np/4
N=length（X）;
N=pow2（nextpow2（N））;
P=pow2（nextpow2（N/L））;
%N=P*L;
%?
%?%?Insert?input?signal?here%
%?%%----------------------------------------------------%%
%?fm=512;
%?fc=2048;
%?A_dc=.5;
%?
%?%??sig=sin（2*pi*（fm/Fs）.*（1:N））‘;
%???c=cos（2*pi*（fc/Fs）.*（1:N））‘;
%?%??sig_phaseshift=cos（2*pi*（fm/Fs）.*（1:N））‘;
%?%??c_phaseshift=sin（2*pi*（fc/Fs）.*（1:N））‘;
%?
%??x=randn（N1）;
%??sig=filter（lp_512Hz_fs8192Hz1x）;
%?%AM_sig=（A_dc+sig）.*c;?%%%%%%%%%%ordinary?AM?Modulation
%?AM_sig=sig.*c;%%%%%%%%%DSB-SC
%?%AM_sig=sig.*c+sig_phaseshift.*c_phaseshift;?%%%%%%%%%SSB
%?%%----------------------------------------------------%%
AM_sig=X;
if?length（AM_sig）????AM_sig（N）=0;
elseif?length（AM_sig）>N
????AM_sig=AM_sig（1:N）;
end
NN=（P-1）*L+Np;
xx=AM_sig;
xx（NN）=0;
xx=xx（:）;
X=zeros（NpP）;

for?k=0:P-1
????X（:k+1）=xx（k*L+1:k*L+Np）;
end

%?windowing?----------------------------------%
w=hamming（Np）;
%XW=diag（w）*X;
XW=X;

%-----------------First?FFT--------------------%
XF1=fft（XW）;
XF1=fftshift（XF1）;
XF1=[XF1（:P/2+1:P）?XF1（:1:P/2）];

%-----------------Down?conversion--------------%
E=zeros（NpP）;
i=sqrt（-1）;
for?k=-Np/2:Np/2-1
????for?m=0:P-1
????????E（k+Np/2+1m+1）=exp（-i*2*pi*k*m*L/Np）;
????end
end
XD=XF1.*E;
XD=conj（XD‘）;
clear?（‘XF1‘‘E‘‘X‘）;

%----------------Multiplication----------------------------%

XM?=?zeros（PNp^2）;
for?k?=?1:Np
????for?c?=?1:Np
????????XM（:（k-1）*Np+c）?=?（XD（:k）.*conj（XD（:c）））;
????end
end
%---------------------------------------------------------%

%-------------------Second?FFT----------------------------%
XF2?=?fft（XM）;
XF2?=?fftshift（XF2）;
XF2?=?[XF2（:Np^2/2+1:Np^2）?XF2（:1:Np^2/2）];
XF2?=?XF2?（P/4:3*P/4:）;
MM?=?abs（XF2）;

alpha0?=?-Fs:Fs/N:Fs;
f0?=?-Fs/2:Fs/Np:Fs/2;
Sx?=?zeros（Np+1?2*N+1）;

for?k1?=?1:P/2+1
????for?k2?=?1:Np^2
????????if?rem（k2Np）?==?0
????????????c?=?Np/2?-?1;
????????else
????????????c?=?rem（k2Np）?-?Np/2?-?1;
????????end
????????k?=?ceil（k2/Np）-Np/2-1;
????????p?=?k1-P/4-1;
????????alpha?=?（k-c）/Np+（p-1）/N;
????????f?=?（k+c）/2/Np;
????????if?alpha<-1?|?alpha>1
????????????k2?=?k2+1;
????????elseif?f<-.5?|?f>.5
????????????k2?=?k2+1;
????????else
????????????kk?=?1+Np*（f?+?.5）;
????????????ll?=?1+N*（alpha?+?1）;
????????????Sx（round（kk）?round（ll））?=?MM（k1k2）;
????????e

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????4134??2009-06-03?22:08??fam.m