How to save a loop data
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Bahaa Algebory
le 22 Oct 2016
Commenté : Walter Roberson
le 24 Oct 2016
Hi guys, I have a for loop, but every iteration overwrites the variable(max_run), and I have only the final data left. How can I save data from every loop? I saw some other questions like my issue, but I always get an error"Improper assignment with
%%BPSK Generation
clear all; close all; clc;
N = 2*10^4; % number of bits or symbols
ip = rand(1,N)>0.5; % generating 0,1 with equal probability
s = 2*ip-1; % BPSK modulation 0 -> -1; 1 -> 1
%%Prepare transmitted signal
m=2; % oversampling factor
beta=0.3; % rolloff parameter for SRRC
l=100; % 1/2 length of pulse shape (in symbols)
chan=[1]; % T/m "channel"
toffset=-0.5; % initial timing offset
pulshap=srrc(l,beta,m,toffset); % SRRC pulse shape
sup=zeros(1,N*m); % upsample the data by placing...
sup(1:m:end)=s; % ... p zeros between each data point
hh=conv(pulshap,sup); % ... and pulse shape
r1=conv(hh,chan); % ... to get received signal
%%Noise Generation
SNRdB=1:2:13; % Signal to Noise Ratio
SNR=10.^(SNRdB/10);
for cv=1:length(SNR);
no=sqrt((1/SNR(cv)))*randn(1,40400); % Noise generation
r=r1+no; % Adding the noise to the received signal
%%Matched Filter & Convolution process
matchfilt=srrc(l,beta,m,0); % filter = pulse shape
x=conv(r,matchfilt); % convolve signal with matched filter
%%Run clock recovery algorithm
tnow=2*l*m+1; tau=0; xs=zeros(1,N); % initialize variables
tausave=zeros(1,N); tausave(1)=tau; i=0;
mu=0.05; % algorithm stepsize
delta=0.1; % time for derivative
while tnow<length(x)-2*l*m % run iteration
i=i+1;
xs(i)=interpsinc(x,tnow+tau,l); % interpolated value at tnow+tau
x_deltap=interpsinc(x,tnow+tau+delta,l); % get value to the right
x_deltam=interpsinc(x,tnow+tau-delta,l); % get value to the left
dx=x_deltap-x_deltam; % calculate numerical derivative
tau=tau+mu*dx*xs(i); % alg update (energy)
tnow=tnow+m; tausave(i)=tau; % save for plotting
indexmin = find(tausave >= 0.5); % finding iteration value..
max_run = min(indexmin) % automaticlly
end
% Plot results
figure, subplot(2,1,1), plot(xs(1:i-2),'b.');
legend([ 'SNR=' int2str(SNR(cv))]); % plot constellation diagram
title('constellation diagram');
ylabel('estimated symbol values')
subplot(2,1,2), plot(tausave(1:i-2))
ylabel('offset estimates'), xlabel('iterations')
legend([ 'SNR=' int2str(SNR(cv))]);
end
1 commentaire
Walter Roberson
le 23 Oct 2016
Are you getting srrc() from http://www.gaussianwaves.com/2011/04/square-root-raised-cosine-filter-matchedsplit-filter-implementation-2/ ?
Réponse acceptée
Walter Roberson
le 23 Oct 2016
max_run(i) = min(indexmin);
4 commentaires
Walter Roberson
le 24 Oct 2016
Your line
xs(i)=interpsinc(x,tnow+tau,l); % interpolated value at tnow+tau
uses an undefined routine interpsinc . I grabbed interpsinc from the File Exchange but you appear to be asking to interpolate all the x values at time tnow+tau and you have over 40000 x values so the result is over 40000 results, which do not fit into the single location xs(i)
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