Questions tagged [cross-correlation]

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Generation of Aysnchronous signals in matlab

I have to develop the MatLab code for a signal to find how the frequency and amplitude content changes during the phase of its propagation from one place to other. It has to do with Coherency losses ...
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13 views

Comparing spectrogram similarity over time

I have a data set of spectrograms from moving audio recorders. As the recorders get closer, I expect the spectrograms to become more "similar". I expect this "similarity" to be a ...
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27 views

Difference between cross correlation definitions (signal processing / random processes)

I'm trying to understand the similarities/differences between the following definitions for cross correlation) Signal Processing: (or it's discrete equivalent) $$R_{XY}(\tau) = \int_{-\infty}^{+\infty}...
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58 views

Which algorithm could be used to compare two waveforms from an oscilloscope in XY mode?

I would like to receive some hint as to which algorithm could be used to compare two waveforms from an oscilloscope in XY mode, as shown in the image: Note that the image shows a percentage ...
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30 views

Blind TDOA Estimation

I am not EE or DSP engineer, however I am working on a project that uses TDOA estimation for location finding. I am able to get the localization algorithm working using cross correlation to estimate ...
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29 views

Cross-correlation estimation in MATLAB using a method similar to pwelch for the PSD

Is there a function in MATLAB to estimate the cross correlation function of two wide-sense stationary signals (or the autocorrelation of the signal with itself) in a way similar to the estimation of ...
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1answer
38 views

What is the difference between Goertzel algorithm and cross correlation in time

Im reading https://en.wikipedia.org/wiki/Goertzel_algorithm, when we want to discover the amplitude of a some frequency in a given signal what is the difference between applying Goertzel algorithm and ...
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27 views

Generating data with given Auto and Cross Correlations

I have two discrete vectors $\mathbf{x}_1$ and $\mathbf{x}_2$, and I'm trying to generate more data $\mathbf{f}_1$ and $\mathbf{f}_2$ that has some basics properties of $\mathbf{x}_1$ and $\mathbf{x}...
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Can cross correlation be used to see if filtering of a signal has changed it too much?

I am filtering a signal, and want to check if I am not over filtering it. I am doing a low pass filter, for a signal of input frequency of 512Hz, first with 250Hz pass band, then )I was intending to ...
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66 views

Impulse response $h[n]$ from input and output signal using cross correlation on Matlab

I have two signals on Matlab, one being input and the other output. I want to know if taking the cross correlation of these signals would give me the impulse response?And if so, will taking the ...
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How to prevent (or remove) aliasing when a cross-correlation between spectra is performed

This is my problem: I'm implementing a tool which cross-correlates a spectrum (fluxes as function of wavelength, obtained directly from an instrument) with a template (fluxes as function of wavelength,...
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60 views

$f \star (g \,* \,h) = (f \star g) * h$?

In this paper that I'm reading, I see this equation: $$S_0 \star (S_0 * N) = N,$$ where $\star$ denotes cross-correlation, $*$ denotes convolution and $S_0 \star S_0 = \delta$. Is it true in general ...
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48 views

Is there any way to align temporally two signals in spectrogram?

I am keen to know that If I have two signals say : Farend_signal (y[n]) and Nearend_signal (x[n]) and x[n] also contains an echo of y[n] with some delay. Is there any technique to align these two ...
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52 views

How to run Welch’s method on cross-spectral density

I have a multivariate time series and I’m trying to figure out the cross spectral density of all pairs of variables efficiently. I’m unsure of how to implement Welch’s method in this context. Do I ...
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111 views

Is `xcov()`More Accurate Than `xcorr()` to Compute the Cross Correlation of Signals with Non Zero Mean Values?

I have to compute the cross-correlation between two transient signals, which could be decomposed into a trend (with non-zero mean value) + noise. In particular I am interested in the max of the cross-...
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79 views

Cross-correlation of two signals

I want to find the direction of a sound source in 2D space. I use two microphones and one sound source for that. I have recorded audio data into two arrays. When a sound is detected, it starts to ...
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1answer
34 views

Map time/scene differences between two similar videos

Goal: Given two videos that are episodes from series but in different format (one Bluray/one TV for example), map the time differences between the two (which scenes are not in one of the two) and be ...
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32 views

Is it possible to normalize an un-normalized cross-correlation vector after computation

I have a C++ code that computes cross-correlation for a given 2 vectors as input. It doesn't have an implicit normalization or normalized implementation of cross-correlation. But I would prefer a ...
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1answer
133 views

CWT at low scales: PyWavelets vs Scipy

Low scales are arguably the most challenging to implement due to limitations in discretized representations. Detailed comparison here; the principal difference is in how the two handle wavelets at ...
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1answer
31 views

Finding delay where squared error between signal and data is minimal

I have a set of points which correspond to part of a known signal. What I want to do is estimate the delay between the set of points and the known signal. In this case, I don't think cross ...
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1answer
75 views

Produce musical signal from instantaneous frequency

I'm implementing the Yin Algorithm in Python so as to extract the pitch of my voice when whistling or humming. My goal is to produce the Gate (Envelop Control) and CV (Pitch Control) signals which can ...
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63 views

How to use cross-correlation to verify speech data and determine delay

I have been experimenting with cross-correlation function to verify the presence of speech in a recorded file wrt a source file. I tried the following in Matlab: <...
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1answer
131 views

Fourier Transforms, Convolution, Cross-correlation: what is their physical unit exactly?

Let us assume we are talking about real, deterministic, electrical signals $x(t)$ and $y(t)$ (magnitude in Volts). There are different kind of Fourier Transforms. I made a table to summarize: NB: By ...
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157 views

Proving the upper bound of cross correlation

I am reading about cross-correlation from this document and equation (5) states that The maximum value of the crosscorrelation is not always when the shift equals zero; however, we can prove the ...
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1answer
60 views

Convolution and Cross Correlation Blackbox

Suppose I was handed a blackbox that I know is either a Convolution filter or Cross-Correlation filter, and my job is to find out which it is. My idea is to pretend that it's Cross-Correlation and ...
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1answer
102 views

GCC-PHAT always peaks at zero when estimating delay offset

My question is that when I used gcc-phat to estimate delay between two audio signals, it always returns zero offset. However normal cross correlation Xcorr gives a good result. I don't know the reason....
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25 views

The normalized cross-correlation of two signals

I wanted to calculate the normalized cross-correlation function of two signals. I use the command ...
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47 views

Strange behavior in fixed-point FFT

This is a problem I encountered some time ago while doing my thesis, which still now, I am not sure to understand. By then, I was implementing the circular correlation in an FPGA using this Xilinx FFT ...
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1answer
92 views

SVD vs matched filter

Reading about singular value decomposition (SVD) in the context of signal processing applications, one can separate the signal from the noise into orthogonal subspaces. On the surface this sounds like ...
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169 views

Fast calculation of normalization factor for normalized cross correlation

There has been a number of posts here I've browsed through that explain implementations of normalized cross-correlation in Python. One such implementation that is frequently cited is found below. <...
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1answer
43 views

Interpreting the cross correlation results

I am new to this forum. I am just trying to understand how to calculate delay (in terms of samples) between two signals using cross-correlation function. I wrote a small Matlab code in order to ...
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2answers
56 views

Comparing similarity of two simultaneously recorded EEGs in freq domain

I have two EEG signals that are simultaneously recorded during the night (sleep). Imagine one device recorded from channel F4 and the other from Fp2. Now I would like to check the similarity of these ...
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1answer
47 views

Matlab: xcorr: Having trouble when I try to calculate delay between two sinusoids

I have a problem when I try to use Matlab built-in function for cross-correlation 'xcorr'. Background: I created two sinusoids, one of them delayed in time. I choose center frequencies of these ...
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aperiodic auto correlation properties

I'm reading about PSC (primary synchronization code) in UMTS. It is a so-called Golay sequence. It is said it has a good aperiodic auto correlation properties. What does it mean (in terms of aperiodic)...
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47 views

Having Problem about DownConversion

I hope, you are doing well. I want to ask question about baseband conversion. Background: I generated two AM signals in MATLAB, which one of them is shifted in time. I multiply the signals with $\cos(...
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318 views

Calculating the bit period

I want to calculate the bit period in my RF packets that I transmit them with 50Kbaud (Symbol rate=bit rate in my case) , how can I calculate the bit period?
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1answer
25 views

Spectral analysis of a cross correlation function [duplicate]

So it's widely known that the Cross Correlation of 2 signals helps us in figuring out the time delay in those signals by analyzing the peak of the correlation coefficient in the time domain. For ...
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1answer
40 views

Cross-correlation with SDPSK modulation

I'm trying to detect a sync word in a signal using Symmetrical Differential PSK (bit 0 = +90° phase, bit 1 = -90° phase). Given the signal is encoded in the phase difference between two symbols, the ...
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60 views

Probability of similarity for two random white noises

I'm looking for the method to calculate theoretical similarity of two random noises $x$ and $y$ with mean $0$ and standard deviation $1$, I've got also $12500$ samples of signal, sampled $2.5$ Ga/s. ...
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138 views

Get the lag of a signal with respect to the other with cross correlation

I have 2 vector of length 20 each. The first 15 entries of $a$ are exactly the same as the last 15 entries of $b$. There is random noise in the 5 last entries of $a$ as well as the 5 first entries of $...
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35 views

Instantaneous frequency, PLLs, frequency mixing, cross-correlation and the cross-correlation matrix

This is as much a request for comment and critique as anything else. I am looking at tracking how a system perturbs an input that is a (real) sinoid of varying frequency. ...
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Clipping cross correlation peak range in noisy signal

The result of a cross-correlating a signal of deltas (period N) with a signal of white noise that's containing a periodic signal (of period N, Length and Position) is plotted in the image. I want to ...
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100 views

Cross Correlation of output with input is equivalent to impulse response of a large bandwidth input (LTI System)?

What is the practical way to found the impulse response of a system ? As impulse function has a very large amplitude at zero time (analog signal). So the cross corelation of output of a large ...
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1answer
41 views

Correlation of discrete time periodic sequences

So I was reading this textbook - Digital Signal Processing by Proakis and Manolakis. The authors define the cross-correlation operation for 2 energy signals $x(n)$ and $y(n)$ in section 2.6.1 as: $$ ...
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84 views

Why Convolve instead of Cross-Correlate for Detection of Known Signal?

I am reading a journal on optimal signal detection by mobile sensor. It is mentioned: How should we plan to robots’ motion in order to maximize the detection probability? Assuming the source emits ...
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182 views

Cross correlation and cross power spectrum for signal + noise

Quick question about my understanding of cross correlations and cross spectral densities. Let $C_{ab}$ be the cross correlation between the signals $a$ and $b$, i.e., $C_{ab}(\tau) = \langle a(t)b(t+\...
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Increasing samples per symbol degrades correlation between signals

I am trying to implement a simple pseudo-noise (PN) ranging simulation. I have used this GNU Radio example, and I have adapted it a bit to suit my needs. Here is a screenshot of my flowchart: The ...
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36 views

CDMA scheme that preserves constant envelope (NRZ/ASK shape)

(This is a followup question to Is this a "valid" CDMA modulation?) Is it possible to find a CDMA scheme in which the receiver can only have a simple slicer? In other words, for the ...
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54 views

Is this a “valid” CDMA modulation?

I am banging my head against (specific aspects of) CDMA for a few days. At the basic level I am confused about the interrelation between implementations that are modeled as mixing and fully digital ...
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1answer
136 views

Calculating PSD, Cross PSD by using FFT outputs

I am having the FFT results of two distinct voice signals. Let's say the FFT results of these two signals are of the form (a+ib) and (c+id). Now, I want to calculate the PSD of each signal and also ...

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