## convolution and arithmetic mean

Started by in comp.dsp8 years ago 2 replies

Hello, I have a discrete signal a(x[i]) = cos(2*pi*x[i]/L). I integrate analytically this cosine function from x[i-1] to x[i+1], I...

Hello, I have a discrete signal a(x[i]) = cos(2*pi*x[i]/L). I integrate analytically this cosine function from x[i-1] to x[i+1], I get exact[i] = L * (sin(2.0*pi*x(i+1)/L) - sin(2*pi*x(i-1)/L)) / ( 2.0*pi). Now, I want to calculate the convolution a * h where h is a rectangular filter (non causal filter). Doing that, I should recover for each node [i] the exact value of the integral (...

## Convolution of same PSDs

Started by in comp.dsp4 years ago 8 replies

Hi, I have a (for simplicity brickwall) bandlimited white Gaussian noise signal x[n]. Hence I know roughly its PSD. I would like to get an...

Hi, I have a (for simplicity brickwall) bandlimited white Gaussian noise signal x[n]. Hence I know roughly its PSD. I would like to get an estimate of ||x^3[n]||/||x[n]||^3 (||.|| l2-Norm of the discrete time signal x[n]). My idea was now to go to frequency domain (Parseval) and obtain the PSD of x^3[n] via 2-fold convolution of X[k]. If I would just approximate the PSD of x[n] as ...

## Question about cross-spectrum and convolution

Started by in comp.dsp13 years ago 1 reply

Hi, I have a question regarding the concept of cross-spectrum, which is defined as the Fourier transform of convolution between two signals...

Hi, I have a question regarding the concept of cross-spectrum, which is defined as the Fourier transform of convolution between two signals X and Y: FT(X*Y) Isn't it the same as: FT(X) FT(Y) My simple clue is: X*Y = IFT( FT(X) FT(Y) ) So, FT(X*Y) = FT(X) FT(Y). Am I right? Thanks

## Circular convolution

Started by in comp.dsp8 years ago 19 replies

I want to write a Matlab code to convolve the two signals: x=[1 2 3 4]; y=[1 -1 3]. I want to do it through circular convolution. Please kindly...

I want to write a Matlab code to convolve the two signals: x=[1 2 3 4]; y=[1 -1 3]. I want to do it through circular convolution. Please kindly any body could help in guiding how to generate the code which should be in generic form that could be used for all signals. Thank you

## Convolution

Started by in comp.dsp11 years ago 2 replies

Dear All, I'm not sure if this is the right place for this, so if not sorry. I have 2 matrixes (2x7) and i want to do convolution on...

Dear All, I'm not sure if this is the right place for this, so if not sorry. I have 2 matrixes (2x7) and i want to do convolution on them. When I do the foureir transformation and then multiply them and finally do the inverse fft I get a matrix of complex numbers. How do I turn these numbers/matrix into a correlation coeff or something close to it. Also is fft-ing the best way to...

## Application for Convolution

Started by in comp.dsp10 years ago 2 replies

http://www.youtube.com/watch?v=WNZCS-coZjY Well she *says* they do it with convolution, which makes sense. "Please try this at home, but not...

http://www.youtube.com/watch?v=WNZCS-coZjY Well she *says* they do it with convolution, which makes sense. "Please try this at home, but not with real guns!" ;) -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com

## Visualising the convolution theorem.

Started by in comp.dsp10 years ago 3 replies

In terms of understanding the convolution theorem i've created the following MatLab code: [ BEGIN CODE] function...

In terms of understanding the convolution theorem i've created the following MatLab code: [ BEGIN CODE] function checkconvolutiontheorem [data Fs] = wavread('pop.wav'); % a 5 second sample of pop-music signal = data(1:453); % Signal consists of 453 non-zero elements. kernel = data(1:60); % Kernel consists of 60 non-zero elements. timesignal = conv(signal,kernel); % Convolution in...

## convolution in matlab

Started by in comp.dsp10 years ago 4 replies

Hi all, I am writing a user defined convolution program in matlab. I have some indexing problems ...please correct and help me with my...

Hi all, I am writing a user defined convolution program in matlab. I have some indexing problems ...please correct and help me with my code: function Out = userconv(a,b) L =length(a);%input M=length(b); %filter t=0; c=zeros(1,L+M-1); % initialize the output data buffer w=zeros(1,M); for i=1 : L+M-1 c(i)=0; for j=1 :M if (i> j) && if ( i-j)

## Equaling multiplication and convolution of a signal

Started by in comp.dsp10 years ago 8 replies

Hello, I am not sure if this is possible, but I have signals x(t) and y(t), and I need to find a signal z(t) that hold the following...

Hello, I am not sure if this is possible, but I have signals x(t) and y(t), and I need to find a signal z(t) that hold the following property: x(t).y(t) = x(t)*z(t); Multiplication of x(t) and y(t) equals to the cyclic convolution between x(t) and z(t). Is there any mathematical approach to find z(t)? Thank you.

## circular convolution or matrix multiplication

Started by in comp.dsp10 years ago 6 replies

Hi, I'm currently doing project on OFDM based. I want to transmit my signal through a Rayleigh channel. assume that the received signal should...

Hi, I'm currently doing project on OFDM based. I want to transmit my signal through a Rayleigh channel. assume that the received signal should be y(t)=x(t)*h(t)+n(t) or Y(f)=X(f)H(f)+N(f). I understand that in order to get y(t), we need to do a convolution between x(t) and h(t). let say, after IFFT in OFDM part, then I change the signal into serial where the data is in time domain. Now, I don...

## [NEWBIE] I need some advice

Started by in comp.dsp15 years ago 1 reply

hi to everyone, I need to find WORKING dsp routines, that is, not vague or damned crypted or totaly wrong routines ( usually these are find...

hi to everyone, I need to find WORKING dsp routines, that is, not vague or damned crypted or totaly wrong routines ( usually these are find in most books). By the way , I want implement a simple ( for you,not for me) procedure to do FFT convolution of large signals ,so I think I must windowing segments of the signal , to make the convolution and to use some type of overlap in order to ...

## Stable convolution feedback

Started by in comp.dsp3 years ago 1 reply

Hi all, I'm hoping to program an effect with convolution, long tap delay and feedback. I'm wondering what some strategies are to keep it from...

Hi all, I'm hoping to program an effect with convolution, long tap delay and feedback. I'm wondering what some strategies are to keep it from feeding back. The idea was to use a sine sweep as the kernel so that each iteration became more slewed. I'm open to altering the kernel as well. Sorry if this is a noob question. Any reading would be appreciated. -Matt

## Convolution

Started by in comp.dsp12 years ago 4 replies

Hallo, I need a help from you. Can anyone please suggest me any links for the topics "convolution of signals", "transformation of signals"...

Hallo, I need a help from you. Can anyone please suggest me any links for the topics "convolution of signals", "transformation of signals" and "different kinds of signals and their equation" in the examination point of view. The lecture material and some books have only very few examples and doesn't gave me much practice. I have searched a lot in the google, but doesn't helps. Thanks, San ...

## complex convolution

Started by in comp.dsp14 years ago 16 replies

Dear All, I would like to convolve two complex sequences. Could anybody help me how to define the convolution of two complex sequences...

Dear All, I would like to convolve two complex sequences. Could anybody help me how to define the convolution of two complex sequences please? Thanks in advanced. Regard, estdev

## fast convolution in Matlab

Started by in comp.dsp15 years ago 2 replies

Does anyone know where I might obtain a Matlab function to perform a fast convolution in Matlab. I have my own but its written in Matlab. I'd...

Does anyone know where I might obtain a Matlab function to perform a fast convolution in Matlab. I have my own but its written in Matlab. I'd like one that was done in C(++), fortran, ect. Speed is an issue. S.M.

## Convolution via FFT

Started by in comp.dsp12 years ago 1 reply

Hi guys, I just added convolution via FFT to my audio program so I can convolve two arbitrary signals (sounds), I have a few questions. In...

Hi guys, I just added convolution via FFT to my audio program so I can convolve two arbitrary signals (sounds), I have a few questions. In Numerical Recipes in C it says to setup the response in wrap-around order, in other tutorials I don't see that being done. Should I be doing that ? Also, if I convolve two signals both in the range [-1.0,1.0] is it normal for the result to be o...

## Deconvolution question

Started by in comp.dsp10 years ago 3 replies

Suppose I have an acoustic guitar with a (relatively good-sounding) peizo pickup (a K&K, for those interested). I can mic the guitar and...

Suppose I have an acoustic guitar with a (relatively good-sounding) peizo pickup (a K&K, for those interested). I can mic the guitar and record the peizo simultaneously. But when I deconvolve the miked signal against the peizo, the resulting convolution signature isn't very coherent. Most convolution signatures of this nature have a "spike" where the dominant bucket is - this has just a ...

## Piecewise Convolution

Started by in comp.dsp5 years ago 7 replies

You know the problems you get at college - convolving a pulse with another pulse or a pulse with a triangular pulse etc. Loads and loads of such...

You know the problems you get at college - convolving a pulse with another pulse or a pulse with a triangular pulse etc. Loads and loads of such examples, many of them start with negative time (ie pulses go from -1 to +1 !). But although convolution as a classical method can be used for solving ODE's what practical use is it? I am not talking about digital or discrete-time convolut

## amplitude spectrum (Convolution & Multiplication) difference

Started by in comp.dsp13 years ago 3 replies

By Multiply the amplitude spectra of the two input time series, and compare the result with the amplitude spectrum of the output series. Check the...

By Multiply the amplitude spectra of the two input time series, and compare the result with the amplitude spectrum of the output series. Check the rule "convolution in the time domain is multiplication in the frequency domain". When I subtract the amplitude spectrum of the convolution from the amplitude spectrum obtained by multiplying the two input amplitude spectra, I observed a difference. Wher...

## GNU C-Graph: Over 100,000 Discover that Visualizing Convolution is Easy

Started by in comp.dsp6 years ago 1 reply

It's Trendy to Visualize convolution with GNU C-Graph! Over 100,000 users discover that learning about the Convolution Theorem can be just a...

It's Trendy to Visualize convolution with GNU C-Graph! Over 100,000 users discover that learning about the Convolution Theorem can be just a few keystrokes away: agt -- -- Freedom - no pane, all gaiGN! GNU C-Graph - http://www.gnu.org/software/c-graph Code Art Now - http://codeartnow.com Caprica Law - https://sites.g