Echo cancellation question (again)

Started by John McDermick in comp.dsp10 years ago 8 replies

Hello, I have made a script which slides a time-window over the speaker signal and the microphone signal. For each window update I save...

Hello, I have made a script which slides a time-window over the speaker signal and the microphone signal. For each window update I save the time lag corresponding to the cross correlation peak value. I had expected to see a more or less constant lag, but instead I see that it is increasing over time. See chart here: http://www.nippyzip.com/uploads/111005105627-44838.zip Wouldn't ...


Correlation Help

Started by brent in comp.dsp10 years ago 5 replies

I am trying to get my terminology correct on saying that "sinx is not correlated with cosx", but..... I know this is not quite true because a...

I am trying to get my terminology correct on saying that "sinx is not correlated with cosx", but..... I know this is not quite true because a correlation function (or in this case a cross correlation function) conducts zillions of integrals on the cosine and sine function as it slides one against the other. When doing the orthogonality test on a sin and cosine , it is essentially doing o...


to calculate time delay between two signals

Started by padma.kancharla in comp.dsp10 years ago 34 replies

HI I am a CS student and new to this field. I am working on source localisation problem. I do not know matlab. Could you please throw...

HI I am a CS student and new to this field. I am working on source localisation problem. I do not know matlab. Could you please throw some light on how to implement the following steps in C language. 1.find the cross correlation between two signals received at two mics simultaneously. Here the signals refer to speech signals. 2.determine the accurate time delay between them. Please giv...


Coherence and Cross Correlation

Started by ayeriera in comp.dsp10 years ago 9 replies

Dear all, I have a simple question that I am trying to confirm, but could not find any clear answer yet. If I want to compute the coherence...

Dear all, I have a simple question that I am trying to confirm, but could not find any clear answer yet. If I want to compute the coherence of two signals (EEG signals in my case) in a particular band (say between 10-13 Hz), is it true that I can do the following? 1) Apply a band-pass filter between 10 and 13 Hz on both signals 2) Compute the cross correlation between both band-pass filt...


Sub-sequence indices for computing FFT cross-correlation between two long sequences

Started by Nicholas Kinar in comp.dsp10 years ago 6 replies

Hello, I need to compute the cross-correlation between two signals x[n] and y[n]. For example, signal x[n] has a length of 3441534 and...

Hello, I need to compute the cross-correlation between two signals x[n] and y[n]. For example, signal x[n] has a length of 3441534 and signal y[n] has a length of 3441528. I only need the cross-correlation at a specific number of lags. In Matlab, I've been doing something similar to the following. This takes up a lot of memory: M = 10000; corrLength = length(x)+length(y)-1; y...


How to recognize the signal?

Started by LVitya in comp.dsp8 years ago 14 replies

I have a signal from sensor. It look like upper part of this...

I have a signal from sensor. It look like upper part of this pictures http://postimg.org/image/l51neenup/ http://postimg.org/image/ddkxfujpd/ I need to recognize two oposite forms of signal: 1) when it goes up then down; 2) when it goes down then up. For example http://postimg.org/image/vxuhwk611/ On this picture 1st forms are marked, 2nd is unmarked. I tried to use cross-correlation (xc...


Something like cross correlation for the time domain

Started by in comp.dsp8 years ago 2 replies

From time to time I have to do cross correlations of signals with different sampling rates. The problem is that I do not know the ratio of...

From time to time I have to do cross correlations of signals with different sampling rates. The problem is that I do not know the ratio of the sampling rate, e.g. because longer recordings are taken with different crystal oscillators for the sampling rate. The idea is to pass two recordings to an algorithm and get the pitch and the delay as result. Strictly speaking the result is two d...


acoustics Comparison

Started by aktr512 in comp.dsp8 years ago 1 reply

Hii I am trying to compare two .wave files(sounds of a device). one is reference file and i have to compare new file with it. how should i...

Hii I am trying to compare two .wave files(sounds of a device). one is reference file and i have to compare new file with it. how should i consider the loudness of sound? i am using cross-correlation , coherence and positive peaks difference techniques in parallel


Correlation functions plot diagrams

Started by runinrainy in comp.dsp7 years ago 3 replies

Hi All, I have a question about the cross correlation of signals x(t) and y(t) which are received from the noisy channel at the receiver. We...

Hi All, I have a question about the cross correlation of signals x(t) and y(t) which are received from the noisy channel at the receiver. We cross correlate the signals and see that there is a peak in the plot diagram of the auto correlation function in time domain. Could someone please explain me what is the meaning of this peak value in the diagram? I am basically trying to interpr...


so i have asked my very first question on the dsp stack exchange site...

Started by robert bristow-johnson in comp.dsp7 years ago 12 replies

ain't ya just proud of me? it's at http://dsp.stackexchange.com/questions/18316/cascaded-cross-correlation doesn't look like...

ain't ya just proud of me? it's at http://dsp.stackexchange.com/questions/18316/cascaded-cross-correlation doesn't look like anyone is taking it up. would anyone here at comp.dsp be willing to look at it? it's about cross-correlation and using it to sorta measure the delay between one signal and another. i would like to know if that delay measure adds when the sorta delay...


C code on Circular Cross correlation of two arrays & interpretation - anyone can post it from Numerical Receipies in C or another?

Started by Anonymous in comp.dsp7 years ago 3 replies

I am looking for a C Program on Circular Cross correlation of two arrays - anyone can post it from Numerical Receipies in C? I did write...

I am looking for a C Program on Circular Cross correlation of two arrays - anyone can post it from Numerical Receipies in C? I did write function and there is a strange bug - just including a printf after the computation alters the values from second index onwards! Secondly, once Circular Cross correlation of two arrays are computed we know at that lag the peak similarity occurs - a


derotating IQ vectors

Started by abal123 in comp.dsp6 years ago 14 replies

Hi, I try to demodulate a received bpsk signal. In order to achive sync, I do a cross correlation of the received signal with a matched filter...

Hi, I try to demodulate a received bpsk signal. In order to achive sync, I do a cross correlation of the received signal with a matched filter (which contains a known preamble). The correlation works well, and I managed to detect a peak at time t0. What is the next step in order to synchronize my receiver? If I compute the phase theta at time t0, how can I do the derotation? Thank you...


Matched filters via cross-correlation

Started by Larry Gadallah in comp.dsp6 years ago 3 replies

Hi all: I am working on a tone receiver that uses cross-correlation to implement a matched filter for the tone. I have frames of samples that I...

Hi all: I am working on a tone receiver that uses cross-correlation to implement a matched filter for the tone. I have frames of samples that I cross-correlate with a frame containing samples of a pure reference tone. My question involves windowing: Should I use a windowing function on each frame? Should the windowing function apply both to the signal frame and the reference frame