I have the measured data from a vector network analyzer. I need to do a autocorrelation in time on this data.
After that I need to look at the time span over which the signal level is -3dB from the maximum.
I am looking for a matlab code for sometime to solve this problem, is there anyone who can help me out?.
I am attaching the 2 files. One with data.csv file and the matlab code so far
clear all;
clc;
DataTbl=fopen('s21versustime6largeabsorbers1000001sec10secsweepusendata.csv');
[Ro,Co]=size(DataTbl);
Data=table2array(DataTbl);
Time=Data(:,1);
S21Mag=Data(:,2);
S21Ang=Data(:,3);
%%% DAta Prep %%%%%%
[Re,Im]=pol2cart(S21Ang,S21Mag);
CmpLx=complex(Re,Im);
ampitude=sqrt((Re .^2)+(Im .^2)); % amplitude value
ampitudedB= 20*log10(ampitude); % amplitude in dB
plot (Time,ampitudedB); %Amplitudein db verus time
you can use this function "xcorr" to make auto-correlation f any data you want: this is an example:
% auto_correlation.m
% This file plots the Auto-cross correlation for symmetric OOC with
% (n,w,1)=(217,4,1)
clear all; clc;
t=-216:216;
x=zeros(1,217); % no. of chips
x(1)=1; x(2)=1; x(16)=1; x(106)=1; % ones position (0,1,15,105)
y=xcorr(x);
plot(t,y)
grid
xlim([-200 200])
ylim([-1 5])
xlabel('Time (chip)')
ylabel('Auto-correlation function')
Dear,
You can check this link, may help you:
dsp.Autocorrelator System object
https://www.mathworks.com/help/dsp/ref/dsp.autocorrelator-class.html
Dear Vikesh,
I know you solved this problem. However, i added an answer to serve as an alternative solution of the problem. Why not calculating directly the autocorrelation function from its definition,
Please see the link:https://dsp.stackexchange.com/questions/15658/autocorrelation-function-of-a-discrete-signal.
Best wishes
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