# Convolution

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sara s 2011 年 12 月 19 日
Hello everybody
Please,I want to do the convolution on my speech signal using conv() How can I do that??
This is my signal
f=8000;
b=8;

#### 5 件のコメント

Naz 2011 年 12 月 19 日
With a sinusoid of 8kHz? Something like modulation? Theoretically, if your voice contains frequencies over 4kHz you will have aliasing. Also, you need to choose how to truncate your sinusoidal signal (the length in time)
Naz 2011 年 12 月 19 日
Convolution with itself? Then just do conv(s1,s1)
sara s 2011 年 12 月 19 日
Yes,I did that previously
But I have this error
??? Error using ==> conv at 27
A and B must be vectors.

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### 採用された回答

Naz 2011 年 12 月 19 日
First of all, this
f=8000;
b=8;
is useless information because it will be rewritten anyway below, unless this information is given to you and you don't fully describe the required task. ASSUMING that your professor wants you to perform convolution of the recorded signal with itself, you can perform this:
s2 = conv(s1(1,:),s1(1,:)); %using all columns from the first row
subplot(2,1,1)
plot(s1(1,:))
subplot(2,1,2)
plot(s2)
Of course, the resulting signal will be nothing like the initial signal.

#### 3 件のコメント

sara s 2011 年 12 月 19 日
I have this error
??? Error using ==> conv at 27
A and B must be vectors.
Naz 2011 年 12 月 19 日
Try replacing both s1 with s1'
Walter Roberson 2011 年 12 月 19 日
Sara has a two-channel wav file so s1 is not a vector.

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### その他の回答 (2 件)

Walter Roberson 2011 年 12 月 19 日
[conv(s1(:,1),s(:,1), 'same'), conv(s1(:,2), s1(:,2), 'same')]
That is for convolving each channel with itself. If for some reason you wanted to convolve left with right, then it would be
conv(s1(:,1), s1(:,2), 'same')

#### 5 件のコメント

sara s 2011 年 12 月 19 日
I have this error
??? Error: An array for multiple LHS assignment cannot contain numeric value.
Walter Roberson 2011 年 12 月 19 日
Please show the traceback of the error -- which line of code it occurred in, which routine, where it was called from, and so on.
Timothy Dixon 2012 年 5 月 18 日
@ sara correct the type error from walter conv(s1(:,1),s(:,1)
correction
conv(s1(:,1),s1(:,1),
s1 was missing. if it does not work, then try to upgrade the version of Matlab that support the recording card system

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Image Analyst 2011 年 12 月 19 日
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
imtool close all; % Close all imtool figures.
clear; % Erase all existing variables.
workspace; % Make sure the workspace panel is showing.
fontSize = 24;
fullFileName = 'C:\Users\N\Desktop\sara.wav';
if exist(fullFileName, 'file')
subplot(2,1,1);
plot(s1);
grid on;
title('Original Signal', 'FontSize', fontSize);
windowSize = 201; % or whatever.
s1_filtered = conv(s1, ones(1, windowSize ) / windowSize );
subplot(2,1,2);
plot(s1_filtered);
grid on;
title('Filtered Signal', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]); % Maximize figure.
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off')
else
uiwait(warndlg(message));
end

#### 17 件のコメント

sara s 2011 年 12 月 19 日
and I just wanted to make convolve the signal with it self and that is enough for me and Thanks a lot Image Analyst,you are very good
Walter Roberson 2011 年 12 月 19 日
There are a number of different filters shown at http://web.mit.edu/1.130/WebDocs/1.130/Software/Examples/example1.m
In that code, you want the vectors that are directly underneath each comment. For example the line under '%Downsampling' is
x = [-1 0 9 16 9 0 -1] / 16;
and that x would be suitable to convolve against.
sara s 2011 年 12 月 20 日
wow Walter thanks so so much ,that is so benefit
Thanks a lot

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