MATLAB: ERROR Subscript indices must either be real positive integers or logicals.

errorthreeldft

clear all; close all; clc
fs=200;     %sampling freq.
dt =1/fs;
N0=fs/50;	%number of samples/cycle
m=3;        %no. of cycles
t = dt*(0:200); %data window
fi=50; %Frequency test
ww=wgn(201,1,-40);
size(transpose(ww))
X=sin(2*pi*fi*t + 0.3)
v = bsxfun( @plus, X , ww  ); 
tmax=1;
% v      :  as function of time
% fs     : sampling frequency (Hz)
% tmax   : time of final estimation
% to test: [t,f]=ZC(@(t)(220*sin(2*pi*50.1*t+pi/2)),50*512,1)
% to test: [t,f]=ZC(@(t)(220*sin(2*pi*50.1*t+pi/2)+randn(1)*.1),50*512,1)
n=N0-1:-1:0;
f0=50;
f=50.88;
Hc=2/N0*cos(2*pi*n/N0+pi/N0);
Hs=-2/N0*sin(2*pi*n/N0+pi/N0);
t_est=[];
f_est=[];
j_max=tmax*fs;
for j=1:j_max+1
	x=v((j-1:j+N0-2)*dt);
    c(j)=x*Hc';
    s(j)=x*Hs';    
    if(j>N0)
        Ac(j-N0)=sqrt(sum(c(end-N0+1:end).^2)/N0);   
        As(j-N0)=sqrt(sum(s(end-N0+1:end).^2)/N0);    
        cc(j-N0)=c(end-N0+1:end)*Hc';
        ss(j-N0)=c(end-N0+1:end)*Hs';
        if(j>2*N0)
            Acc(j-2*N0)=sqrt(sum(cc(end-N0+1:end).^2)/N0);   
            Ass(j-2*N0)=sqrt(sum(ss(end-N0+1:end).^2)/N0);   
            ccc(j-2*N0)=cc(end-N0+1:end)*Hc';
            ccs(j-2*N0)=cc(end-N0+1:end)*Hs';
            ssc(j-2*N0)=ss(end-N0+1:end)*Hc';
            sss(j-2*N0)=ss(end-N0+1:end)*Hs';
            ff=f0*N0/pi*atan(tan(pi/N0)*((ccc(j-2*N0).^2+ccs(j-2*N0).^2)./(ssc(j-2*N0).^2+sss(j-2*N0).^2)).^.25);
            t_est=[t_est;(j-1)*dt];
            f_est=[f_est;ff];
        end
    end
end
t_est
f_est
plot(t_est,f_est,'red')
o=rms(fi);
c=rms(f_est)
RMSE = sqrt(mean(c - o).^2)
t_est;
f_est
plot(t_est, f_est,'red')
hold on
RMSE = sqrt(mean((f_est-fi).^2))
xlabel('time')
ylabel('frequency')
title('three LDFT white noise')
   plot (t_est,fi*ones(size(t_est)))
hold off
Subscript indices must either be real positive integers or logicals.
Error in threeDFT (line 35)
x=v((j:j+N0-2)*dt);

Best Answer

for j=2:j_max+1
	x=v((j-1:j+N0-2)*dt);
Use a positive non zero integer subscripts. In your case it is zero
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