This is the code for FFT Accumulation Method using autocorrelation.correct this code .we are receiving an error as Function definitions are not permitted in this context.

clc;
clear all;
close all;
Tu=224e-6; 
T=Tu/2048; 
G=0;
delta=G*Tu; 
Ts=delta+Tu;  
Kmax=2000; 
Kmin=0;
FS=4096;
q=10;
fc=q*1/T;
Rs=4*fc;
t=0:1/Rs:Tu;
M=Kmax+1;
rand('state',0);
a=-1+2*round(rand(M,1)).'+i*(-1+2*round(rand(M,1))).';
A=length(a);
info=zeros(FS,1);
figure(1);
stem(a );
info(1:(A/2)) = [ a(1:(A/2)).'];
info((FS-((A/2)-1)):FS) = [ a(((A/2)+1):A).'];
carriers=FS.*ifft(info,FS);
tt=0:T/2:Tu;
figure(2);
subplot(211);
stem(tt(1:100),real(carriers(1:100)));
title('subcar generation');
subplot(212);
stem(tt(1:500),imag(carriers(1:500)));
figure(3);
f=(1:(FS))/(FS);
subplot(211);
plot(f,abs(fft(carriers,FS)/FS));
x=real(carriers);
fs=4096/Tu;
df=1/Tu;
dalpha=2098/Tu;
function [Sx, alphao, fo] =autofam(x, fs, df , dalpha)
Np=pow2 (nextpow2 (fs/df ) ) ;
L=Np/4;
P=pow2 (nextpow2 (fs/dalpha/L))
N=P*L;
if length (x) <N
x(N)=0;
elseif length (x) >N
x=x(l:N);
end
NN= (P-l) *L+Np;
XX=X;
Xx(NN)=0;
xx=xx ( : );
X=zeros (Np, P);
for k=0:P-l
X( : ,k+l) =xx(k*L+l:k*L+Np);
end
a=hamming (Np);
XW=diag(a) *X;
XW=X ;
XFl=fft (XW);
XFl=fftshift (XF1);
XF1= [XF1(:,P/2+l:P) XF1(:,l:P/2) ];
E= zeros (Np, P);
for k=-Np/2:Np/2-l
for m=0:P-l
E(k+Np/2+l,m+l) =exp(-i*2*pi*k*m*L/Np);
end
end
XD=XF1.*E;
XD=conj (XD' );
XM=zeros (P,Np^2) ;
for k=l:Np
for l=1:Np
XM(:,(k-l)*Np+l)=(XD(:,k) .*conj(XD(:,1) ) );
end
end
XF2=fft (XM);
XF2=fftshift (XF2);
XF2= [XF2(:,Np^2/2+l:Np^2 ) XF2(:,l:Np^2/2) ];
XF2=XF2 (P/4 : 3*P/4 , : );
M=abs (XF2);
alphao=-l:l/N:l;
fo=-.5:l/Np: .5;
Sx=zeros (Np+1, 2*N+1)
for kl=l: P/2+1
for k2=l:Np^2
if rem(k2,Np) ==0
l=Np/2-l;
else
l=rem(k2,Np) -Np/2-1;
end
k=ceil (k2/Np) -Np/2-1;
p=kl-P/4-l;
alpha= (k-1) /Np+ (p-1) /L/P;
f=(k+l)/2/Np;
if alpha<-l | alpha>l
k2=k2+l;
elseif f<-.5 | f> .5
k2=k2+l;
else
kk=1+Np*(f+.5);
ll=1+N*(alpha+1);
Sx(kk,ll) =M(kl,k2);
end
end
end

Answer 1

[John D'Errico]

Older releases of MATLAB do not allow functions to be defined as part of script. So either learn to save your functions as an m-file, or get a current release of MATLAB.