Subscripted assignment dimension mismatch // Overlap Save Method

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MatlabGirl 2014-12-8

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/165877-subscripted-assignment-dimension-mismatch-overlap-save-method

评论： Guillaume 2014-12-8

在 MATLAB Online 中打开

I don't know why this happens

The code works fine for L = 5 only however I need to be able to vary L without issues

here is my code

clc;
clear all;
close all;

2nd order filter

filter_2 = firceqrip(2,0.6,[0.05 0.03]);
% impulse response in time & freq domains (order 2)
[h_2 t_2]= impz(filter_2);
% We are given 4 different frequencies 
freqs = [0.08, 0.2, 0.32, 0.4];
periods = 1./ freqs;
% Let the max value of t be 4 times the largest period
t_max = 4 * periods(1);
% Let us have 50 samples over the interval [0, t_max].
t = linspace(0, t_max, 50);
% The synthesized signal 
signal = sin(2*pi*0.08*t) + sin(2*pi*0.2*t) + sin(2*pi*0.32*t) + sin(2*pi*0.4*t);
x = signal;
h = h_2;
L=5;
% % Code to plot X(n)
% subplot (2,2,1);
% stem(x);
% stem(x,'blue');
% xlabel ('n');
% ylabel ('Amplitude');
% title('X(n)');
% 
% %Code to plot H(n)
% subplot (2,2,2);
% stem(h);
% stem(h,'black');
% xlabel ('n');
% ylabel ('Amplitude');
% title(' H(n)');
% Code to perform Convolution using Overlap Save Method
M=length(h);
lx=length(x);
r=rem(lx,L);
x1=[x zeros(1,L-r)];
nr=(length(x1))/L;
h1=[h' zeros(1,L-1)];
for k=1:nr
    Ma(k,:)=x1(((k-1)*L+1):k*L)
    if k==1
        Ma1(k,:)=[zeros(1,M-1) Ma(k,:)];
    else 
        Ma1(k,:)=[Ma(k-1,(L-M+2):L) Ma(k,:)];        
    end
     Ma2(k,:)=ifft(fft(Ma1(k,:)).*fft(h1));
end
Ma3=Ma2(:,M:(L+M-1));
y1=Ma3';
y=y1(:)'
% Representation of the Convoled Signal
figure
subplot (313);
plot(y,'red');
xlabel ('n');
ylabel ('Amplitude');
title ('Convolved Signal, using 4 samples');

your help is appreicated

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MatlabGirl 2014-12-8

编辑：MatlabGirl 2014-12-8

It happens only if L is not equal to 5 Which is weird

Guillaume 2014-12-8

I'll repeat what I asked: show us the whole error message (everything in red), particularly the bit that shows the line where the error occurs.

What are the values of M, L, lx, r when the error occurs?

None of the variable names in your code mean anything, so it's near impossible to follow what's going on. The only variable with a meaningful name, signal, gets immediately renamed to x unfortunately.

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