Hello, This is probably a classic problem, but after much Googling, I can't come up with the right keywords. In the following, * is a...

Hello, This is probably a classic problem, but after much Googling, I can't come up with the right keywords. In the following, * is a convolution (conv in Matlab) ^2 means squared ( .^2 in Matlab) and a dot . means multiply (.* in Matlab). I would like to be able to "factor" a filter h into two filters h1 and h2 in such a way that for any signal s: (s^2) * h = (s*h1) . (s*h2) Any...

Hi, I have a DTFT function Y(w) which is also a function of a: Y(w,a) (it's actually a sum with a as coefficient) Another function Yl(w) is...

Hi, I have a DTFT function Y(w) which is also a function of a: Y(w,a) (it's actually a sum with a as coefficient) Another function Yl(w) is the l-fold convolution of Y: Yl(omega) = Y(w) * ... * Y(w) \ / l-times Now I want to take the derivative wrt. c, so I do: dYl(w)/dc = dYl(w)/dY(w) * dY(w)/dc Y and Yl are continuous functions, so t...

Hi Fred, Thanks a lot for the prompt response. I've now got the hang of it. It is reassuring that my thought process is compatible with...

Hi Fred, Thanks a lot for the prompt response. I've now got the hang of it. It is reassuring that my thought process is compatible with your clarification, save for the incorrect semantic usage of "present" to state the input x(n) and response h(n). To re-state what you've said: x(1) has to butt(align) with h(1). Another question: Why use dummy variable Tau? How does one arrive at h(t...

If the noise includes some DC it seems that a matched filter would treat it as a zero frequency "curve" and eliminate it in the convolution...

If the noise includes some DC it seems that a matched filter would treat it as a zero frequency "curve" and eliminate it in the convolution along with all the higher frequency noise. Bret Cahill

Hi. I have an application that 90% of the time, the CPU is doing a 2 dimensional convolution using FFTs. Numerical Recipes mentions number...

Hi. I have an application that 90% of the time, the CPU is doing a 2 dimensional convolution using FFTs. Numerical Recipes mentions number theoretic transforms as as possibly far superior in speed for convolutions. But that was it. Does anyone have code to do a number theoretic transform for 2D convolutions? Thanks

hi, all try this in matlab. convolve any random signal with itself several times (atleast 10 iterations). you will get output as...

hi, all try this in matlab. convolve any random signal with itself several times (atleast 10 iterations). you will get output as gausssian. sample code: t=00:.01:.99; b=square(2*pi*t); % input may be any shape b=conv(b,b); b=conv(b,b); b=conv(b,b); b=conv(b,b); b=conv(b,b); b=conv(b,b); b=conv(b,b); plot(b);

Hi, I have two signals, one sampled at 1ms (ricker), the other anything greater, 4 or 5 or 10ms. I need to do a convolution, that is...

Hi, I have two signals, one sampled at 1ms (ricker), the other anything greater, 4 or 5 or 10ms. I need to do a convolution, that is a multiplication in freq. domain. My question is, given that the second signal is a series of spikes, do I need to use some sort of interpolation (e.g. sinc) or is it enough to add samples (zeros) between the spikes, depending on the ratio of the signals sampli...

Further to Robert's peer review, and the then swapping around of the multiply / divide words. hopefully correct at last...

Further to Robert's peer review, and the then swapping around of the multiply / divide words. hopefully correct at last ... -----ooooo----- Revised after peer review, approached with a little less haste So... Sampling with a period of T is given by (after asciification) as .. (T)sum (n : 0, inf)(d(t-nT) * f(nT) ) ... with * representing multiplication and not convolution as w...

Hi guys, I have a theoretical relationship that variable z = convolution(x, y ). I now have vectors of z and x and I am trying to deconvolute...

Hi guys, I have a theoretical relationship that variable z = convolution(x, y ). I now have vectors of z and x and I am trying to deconvolute them to get vector y. I tried to to FFT to solve for y. The problem is that I also got some oscillation in the y vector while there should be none. The shape of the vectors z and x all look like bell shape and they look pretty smooth. They are close to z...

Hi all: I want to write some program about convolution,fourier transform for the signals and systems course. It's easy to write the...

Hi all: I want to write some program about convolution,fourier transform for the signals and systems course. It's easy to write the programs in Matlab,but I don't know does the .m file can be executed in a web page? Some demos searched from web all use javaapplet,So I wonder is there any other way to show how the algorithm works. Thanks.

So some of the papers I am looking at represent convolution in 'matrix' form in one of two ways: y[n] = H^H * X where H^H = hermitian (conj...

So some of the papers I am looking at represent convolution in 'matrix' form in one of two ways: y[n] = H^H * X where H^H = hermitian (conj transpose) of filter H and y[n] = H^t * X where H^t = transpose of filter H Why is the first formula conjugated? To get a better sense of what I mean..incase my notation above is confusing you. I am trying to understand why on wikipedia the form...

Hello all, I have a few questions concerning GMSK modulation in the GSM physical layer. My simulation is done in MATLAB, processed 148 bits and...

Hello all, I have a few questions concerning GMSK modulation in the GSM physical layer. My simulation is done in MATLAB, processed 148 bits and follows the quadrature baseband implimentation method presented in: http://www.emc.york.ac.uk/reports/linkpcp/appD.pdf. 1. I am not sure that I understand correctly the convolution with the Gaussian filter. What I do is : BT = 0.3; T = (3.69*10...

This is a program I found in the book named: DSP using Matlab v4.0. I think it's quite popular since I can easily find in on the Internet using...

This is a program I found in the book named: DSP using Matlab v4.0. I think it's quite popular since I can easily find in on the Internet using google. Many website provide its source code It's about Circular convolution: ---------------------------------------------------- function y = circonvt(x1,x2,N) if length(x1) > N error('N must be > = the length of x1') end if length(x2) >

Given that x(t)*h(t) X(w)H(w), can we obtain x(t)h(t) (1/2PI)X(w)*H(w) by using only the duality property of Fourier transform? THanks!

Given that x(t)*h(t) X(w)H(w), can we obtain x(t)h(t) (1/2PI)X(w)*H(w) by using only the duality property of Fourier transform? THanks!

I did search the groups for fast convolututions,but did not find the answer relevent to my research.So here is the question. I use a gaussian...

I did search the groups for fast convolututions,but did not find the answer relevent to my research.So here is the question. I use a gaussian to smoothen the image.Making the filter seperable (in row and column) is the normal approach(unless you have a lot of time to process a 2D gaussian).I am NOT doing recursive filtering,just filtering it once.Some of the approaches I came across are ...

Hi, I have a load of mass spec (maldi-tof) data that I need some help working with. At any time index t, there is a corresponding mass as...

Hi, I have a load of mass spec (maldi-tof) data that I need some help working with. At any time index t, there is a corresponding mass as determined by the coefficients from a quadratic. I would like to try to maximize my correlation by convolving my actual spectra with the expected signals. The problem is that I dont know how to adjust my coefficients in a coordinated fashion wi...

Hi, I am somewhat new to the world of DSP and my math skill need a lot of push-forward. So the question may be fairly basic and the answer...

Hi, I am somewhat new to the world of DSP and my math skill need a lot of push-forward. So the question may be fairly basic and the answer is probably quite simple but I am having a hard time to figure it out. So say I have a signal x(n) and I want to convolve it with x(-n). Let's call the operator sum from k = -INF to INF as S. So if I take the first variable as x(-n) then from the conv. ...

Hello, there, the notes I have read on convolution state that when I convolve a signal of M samples with another signal of N samples the...

Hello, there, the notes I have read on convolution state that when I convolve a signal of M samples with another signal of N samples the output signal will be (M+N-1) samples. Who can prove for me this mathematically?

hello everyone, i just downloaded the FFTW library, and i read the tutorial (well..i skimmed through it). i'm using dev-C++. in c++, i...

hello everyone, i just downloaded the FFTW library, and i read the tutorial (well..i skimmed through it). i'm using dev-C++. in c++, i constructed 2 vectors, and i have to convolve them using the FFTW library. the stuff in the tutorial seems much more complex than what i want to do, and i am a newbie. a really slow learning newbie that needs guidence. so, i was wondering if anyone could pleas...

Hello everyone, I need help on this one. I am trying to use FFTW to compute the integral of x^-4 and some smooth on/off signal first in 1D....

Hello everyone, I need help on this one. I am trying to use FFTW to compute the integral of x^-4 and some smooth on/off signal first in 1D. But already here I am experiencing some scaling problem by a factor close to 3. This is what I do (after reading bunch of web pages) for a N sampling: 1. compute N points of the functions between -L and L. 2. wrap around the response function (x^-4) in ...