Questions tagged [cross-correlation]
The cross-correlation tag has no usage guidance.
371
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Cross Ambiguity Function Peak Width
I am trying to plot the Cross Ambiguity Function of two OFDM signal (1024 subcarriers) reflected from two targets, which are separated by 30m.
The problem I am facing that the CAF peak width at the ...
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Covariance of 2D cross correlation result
I am trying to align two 2D signals with one unique correct alignment.
After applying 2D cross-correlation on the signals I get results such as these:
bad/degenerate peaks:
good peaks:
decent peak: ...
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Find offsets of two audio files with several sections in common
I have two audio files that have mostly identical* content, most of which is just people talking. A typical example would be two files, each approximately an hour long, in which ~55 minutes of the ...
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Cross-correlation seems defined backwards
Suppose $f$ and $g$ are real. Why
$$
C(\tau)=(f\star g)(\tau) = \int_{-\infty}^{\infty} f(t) g(t + \tau)dt \tag{1}
$$
and not
$$
C(\tau)=(f\star g)(\tau) = \int_{-\infty}^{\infty} f(t) g(t - \tau)dt\...
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Is maximum cross-correlation achieved at the origin?
Let $x[n]$ and $y[n]$ be two DT random signals with $x[n]\xrightarrow{\mathcal{H}}y[n]$ through some system $\mathcal{H}$ that is deterministic yet unknown.\
Define both the autocorrelation and cross-...
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Delay/Lag calculation using cross correlation in frequency domain
I need to compute cross correlation of two signals using frequency domain. Hence, I am using the below equation for calculation.
max(IFFT(FFT(a)*conj(FFT(b))))
...
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Cross-correlation threshold for phase and time synchronization
I have a question regarding correlation-based synchronization. In particular, I'm interested in learning more about how to set a threshold. I currently use a percentage (around 90%) of maximum ...
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Resolution of phase measurement using cross Correlation
The setup is the following:
I am using a RedPitaya board to measure the phase shift of two input signals. These input signals will sweep logarithmically from 1kHz to 100 kHz in 10 seconds.
Currently, ...
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1
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Cross-correlation maximum in frequency domain
I need to compute the complex cross-correlation between two signals a and b and the take only the maximum value of the cross-correlation, regardless of the lag time where this occurs. I can do it ...
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Synchronization for busty signals by correlation methods
I'm trying to reuse standard synchronization algorithms for phase(Costas) and Time (Polyphase Filter bank) for receiving bursty signals. The bursty signals are transmitted every 5 seconds. The signals ...
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Can multiple cross-correlation be expressed in terms of multiple Fourier transforms?
A post explains that the cross correlation of two signals can be given by $$\mathcal{F}^{-1} \left\{\mathcal{F}\left\{x(t) \right\} \mathcal{F}\left\{y(t) \right\}^* \right\}$$
Does this generalize to ...
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Linearity of the system with Pearson correlation sliding window
I have a sampling system that consists of linear and non-linear components(analog filters, ADC, CPU, and so on). I made some HW changes and I want to verify that the linearity was preserved.
My method:...
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What transformation preserves first term and averages the opposite conjugates?
I can't figure not find any reference on what is this transformation (what $X$ represents in relation to $A$).
If $A=[a_1+jb_1, a_2+jb_2, a_3+jb_3, ..., a_n+jb_n]$, $X$ is defined as:$$X=\left[j b_1, \...
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Confusion In DC power,Average Power,Ac Power and total Power
These are Things I studied.
$ E[X]:-$ THis gives us Average value or Dc value
$E[X^2]:-$Total power
$\sigma^2=E[X^2]-E[X]^2$:-Ac power
From Autocorrelation
$R_x(0)=E[X^2]$--Total power
And $ \lim_{x\...
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Y axis Component of Rxy in MATLAB
I calculated the $R_{xy}$ by cross-correlating $x(n)$ and $y(n)$.
Now, in the MATLAB command window, I wish to construct the Y-axis component of $R_{xy}(n)$. I'm not sure how I'm going to do it. Is ...
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How can I generate X Axis componant in R_xy in MATLAB?
Let's say I have cross-correlated $x(n)$ and $y(n)$ and got the $R_{xy}(n)$.
Now if I want to generate the x-axis component of $R_{xy}(n)$ in the command window of MATLAB. How can I do that? is there ...
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Failing to use Cross-Correlation to find position of measurement sequence in data-stream
Recently I used two measurement systems to record a quantity. I made sure both use the same sampling frequency. One system was recording continuously while the other one was operated to only record ...
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Computing Phase Difference Between Two Channels from SDR
I'm trying to compute the phase difference between two channels of a software-defined radio. I'm providing code for two different methods that I'm trying below. In both cases, I'm transmitting a pure ...
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Difference between reference and measurement signal?
Which differences can we find on various signals? We assume that we have a reference signal (determined theoretically) and measured signal.
Which methods exist for determining the similarities ...
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2D space and 1D time evolution of a random field
I also asked this on math stack-exchange, but it is also relevant for the signal processing community.
I want to develop a 2D random field and its change with time with constant velocity. My process:
...
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MATLAB filter and conv Functions
I'm trying to get familiar with MATLAB's filter and conv functions. To start, I created a signal that was 1000 zeroes followed by a 13 sample long Barker code. I then convolved it with the same Barker ...
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Auto/cross correlation for data set with multiple realizations
Context
For an assignment, I need to find the correlation matrix of a dataset with 100 random variables and 1000 realizations for each. (It's a stock market example).
Problem
I don't understand how ...
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xcorr MATLAB is not giving accurate result in case of noisy signals
I've a signal $x(n)$. I've generated its delayed copy named $x1(n)$ and applied xcorr function of MATLAB to find out the delay. It gives accurate delay.
Now I ...
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What is the effect on the cross-correlation of two windowed signals?
I've been trying to determine the effect of performing the cross-correlation operator on two windows signals.
For example: suppose we have two Sinc functions. The Sinc function is defined as $\frac{...
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633
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scipy cross-correlation: interpretation
I want to compute the phase shift between two 1-D signals of same frequency, but before I'm trying to compute the time shift between. The cross-correlation function seems to be ideal for that but I'm ...
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Finding the Right Image-Matching Algorithm for Brightfield Microscopy Data
I work predominantly on single-particle-localization algorithms for microscopy data, but we're working to implement a few different methods to extend our tracking methods nicely into the z-axis.
One ...
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57
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Why is peak of the signal taken as the Time Delay
I was reading this research paper titled 'The generalized Correlation Method for Estimation of Time Delay' by C. Knapp and G.C. Carter. They develop an ML estimator and in the introduction mention ...
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133
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Relation between bandwidth and amplitude of auto correlation of chirp signal
I am trying to understand the properties of chirp signals and their characteristics.
I plotted the autocorrelation of a chirp signal in MATLAB.
How can I compute the relation between the amplitude of ...
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127
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Estimate the time delay of two signals
I am having 2 sets of data data1 and data2 .I wanted to find the delay between the two datasets.
Assume data1=[1 2 3 4 5 6 7 8 9 10] and data2=[0 0 0 0 1 2 3 4 5 6].From the data I know that, data2 is ...
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Method to generate binary sequences with desired cross-correlation and autocorrelation properties
I am looking for a method to generate two binary sequences of length $N$ with the following properties:
Very good cross-correlation for all shifts.
Good enough autocorrelation for all shifts except ...
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RF-Chain Signal Delay for Sensor Switching
Lets have a RF-chain as above with system bandwith from HP corner to the green line say 1 MHz.
The signal accumulates delay as it passes through this analog chain, and due to it being non-liner filter ...
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Extraction of the phase lag form cross-correlation function
I would like to find out the phase offset that my signal contains at the receiver side. For this, I use the cross-correlation function, where I cross-correlate signal before and after matched filter. ...
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How does a correlation receiver ensure which transmitted data does a user see?
Hello! I understand that using correlation, one can set up a system wherein multiple users can transmit at the same time using the same channel. And theoretically, I understand that if the correlation ...
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Real Data Complex Transfer Function using H0, H1, H2 Estimators
BACKGROUND:
This question is attempting to consolidate material discussed in two previous topics. These are:
Understanding the H1 and H2 estimators @Pontus S
Frequency-domain deconvolution: "...
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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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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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2
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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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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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67
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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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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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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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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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$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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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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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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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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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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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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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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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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