MATLAB Answers


Why matched filter in Simulink does not return the same results like in Matlab?

Asked by Marcin Puchlik on 31 Oct 2018
Hi, I have a problem with matched filtering. In Matlab I create a script:
if true
noise_real = wgn(1,1000,5);
noise_imag = wgn(1,1000,5);
noise_complex = complex(noise_real,noise_imag);
noise.time = [];
noise.signals.dimensions = 1;
noise.signals.values = [noise_complex].';
template = noise_complex(400:499);
coeffictions = conj(template(end:-1:1));
coef.time = [];
coef.signals.dimensions = 1;
coef.signals.values = conj(template(end:-1:1)).';
mf_output = filter(coeffictions,1,noise_complex);
which provides me perfect matched filtration of generated noise. I wanted to create the same filtration in Simulink using "From Workspace" blocks separately for coefficients with cyclic repetition feature. I wast trying few kinds of filters without any result. I mean that I can't get the same plot from Simulink as I got from Matlab using metioned script. I am enclosing plot from matlab and simulink for comparison. Question is: how filter in Simulink works? Do they upload all samples and after accumulation of enough samples starting to perform convolution? How schould I perform my computation to obtain the same result like in Matlab. Thanks


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