Questions tagged [cross-correlation]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
1
vote
0answers
44 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. ...
0
votes
2answers
123 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 ...
1
vote
1answer
48 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: $$ ...
0
votes
2answers
124 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 ...
1
vote
2answers
232 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+\...
1
vote
0answers
35 views

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 ...
0
votes
1answer
40 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 ...
0
votes
1answer
63 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 ...
0
votes
1answer
254 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 ...
0
votes
1answer
126 views

Calculating Cross Power Spectral density between two complex signals

I have a small misunderstanding of cross power spectral density between two complex signals. I know that it is the Fourier transform of cross correlation between two signals. Let's say the complex ...
0
votes
1answer
167 views

How to find correlation between two signals regarding peaks?

In a super-resolution task, I try to predict the higher frequencies of a signal. X low-resolution (lr) is my input and Y high-resolution (hr) is the target. Where X contains only frequencies till 2 ...
-1
votes
1answer
96 views

Why Cross-correlation work better than Generalized Cross-correlation GCC-PHAT in MATLAB?

Fs = 192000; t = 0:1/Fs:(0.01-(1/Fs)); F1 = 10000; x = 1*sin(2*pi*t*F1); nSamplesGausswin = length(t); w = (gausswin(nSamplesGausswin))'; s = w .* x; this is ...
3
votes
2answers
795 views

Convolution v.s. Cross Correlation in Digital Image Processing

I understand that from mathematical point of view, only difference between Convolution and Cross Correlation is that Convolution is commutative, while Cross Correlation is not. In many articles ...
0
votes
0answers
187 views

Why are the Fourier transforms of autocorrelation and cross-correlation different?

I'm almost definitely misunderstanding this, but as far as I can tell we can equate the Fourier transform of the auto-correlation function $R_{xx}(\tau)$ with power spectral density (PSD) like so: $\...
1
vote
1answer
33 views

Variance of circular vector correlation

Say I have two zero-mean vectors, with a size of N and the translation between them is k. Say the image signal std is $\sigma_s$ and the noise std is given by $\sigma_n$. What is the variance of the ...
0
votes
0answers
21 views

What happens to crosscorrelation of two noise generator if one of them were to be inverted

I have two noise generator u1 and u2 and their crosscorrelation is given, what will happen to this crosscorrelation if u2 or u1 were to be inverted?
1
vote
0answers
57 views

How to extract information about each constituent 'wave' of a signal?

I have a vector containing wind speeds sampled at 1Hz over ten minutes. I have applied a lowpass filter of 0.25Hz to get only the wind speeds I am interested in. I now want to use MATLAB to ...
0
votes
1answer
38 views

Synchronize device to audio stream - Approach

I am working on a device which's actions should be synchronized to the audio played. The audio stream is known in beforehand and can be altered to contain signals for the synchronization. But the ...
0
votes
1answer
159 views

Difference Fourier Shift Theorem and Cross Correlation Theorem

can someone explain me the difference between the Fourier Shift Theorem and the Cross Correlation Theorem? The shift theorem says that a delay in the time domain corresponds to a linear phase term ...
0
votes
2answers
77 views

Transforming digitized noisy signal before applying cross-correlation

I'm trying to grasp the concept of cross-correlation as it applies to CDMA in the GPS C/A signal where noise is involved and the SNR is low. My understanding is that before calculating the cross-...
0
votes
1answer
154 views

Autocorrelation Computation with MATLAB

I have done the computation of the autocorrelation of a sequence (vector), here called "frame", and I have plotted it. Here the code: The resulting graph is: I do not understand the position of the ...
0
votes
0answers
441 views

Matlab normxcorr for 1D signals

I am very surprised not to find a version of normxcorr2 for 1D signals in Matlab ! I implemented something like that by hand (with 2 for loops, and normalizing the template as well as the window under ...
2
votes
0answers
76 views

Simulink cross correlation issue

here is the Simulink model that i'm using : The matlab function script : function tau = fcn(sig,refsig) tau = gccphat(sig,refsig); The errors :
3
votes
1answer
47 views

Synchronising audio in realtime without knowledge of original signal

Was doubting whether this is the right SE forum to ask my (elaborate) question, so don’t hesitate to let me know if it’s not. Also, if anyone knows of a better way to title the question, feel free to ...
0
votes
3answers
381 views

How to reliably compute the group delay of a comb filter

I applied the following FIR comb filter in real-time: y[n]=x[n]-x[n-40] Since this is an FIR, the group delay is D=(N-1)/2=20 samples. After applying the filter ...
2
votes
1answer
87 views

Deriving the Langrangian interpolation polynomials in Cook-Toom convolutions

I'm working through Blahut's 'Fast Algorithms for Signal Processing'. Trying to develop an intuition for the Cook-Toom algorithm for convolutions as used by Lavin and Gray in their Winograd paper for ...
2
votes
1answer
251 views

GCC-PHAT for Multiple Sound Sources

Can GCC-PHAT be used to detect multiple time-delays (that is, having multiple acoustic sources simultaneously)? The documentation for the gccphat(sig,refsig) ...
1
vote
0answers
42 views

Pearson correlation coefficient vs mutual information

I recently computed both the pearson coefficient and the mutual information of two time series as well as the corresponding error bars, and what I find out in the end is a significant level of ...
1
vote
1answer
254 views

Cross correlation to compute delay between two lines does not work

I have zero experience with signal processing, and I am stuck in what I believe to be a very simple problem. I am trying to use the xcorr in matlab to find delay between two signals. The signals are ...
2
votes
1answer
183 views

Reduce noise of sensor by combining two

I've had the basics of signal in university but little real-life practice. I've got an acceleration sensor with a digital output signal (signed 16 bit value). This signal is a little noisy. The ...
2
votes
1answer
281 views

Discrete Time Fourier Transform (DTFT) cross correlation property

I came across this property of the Discrete Time Fourier Transform (DTFT) and I am having a tough time proving it. In general, consider two real signals $x[n] \: \& \: y[n]$. If $$ x[n] \...
3
votes
2answers
450 views

Is maximizing hamming distance the same as minimizing correlation?

For the design of an error correcting code, I might wish to maximize the distance between the codewords $\sum a_i \oplus b_i$. For spreading sequences I'd like to minimize the cross-correlation at $t=...
3
votes
1answer
247 views

Strong (0,0) pixel among an otherwise normal cross correlation peak

I am working on an imagery registration problem via cross-correlation and am seeing a weird phenomena sometimes. First, I am pre-processing each image by subtracting the mean image brightness from ...
1
vote
1answer
63 views

Phase lag changes cross spectrum

I have a same noise passing through two different ARMA filter. The autospectrum of first filter is given by S11=G1*G1*S_in where S_in is input spectrum created by set of random numbers. Similarly the ...
2
votes
2answers
4k views

How to compare and measure the similarity between two between two signals?

I'm working on different sensors data, the question is this: I have two signals (coming from two different sensors measuring two different phisical charactheristcs of the same "object"). I know for a ...
1
vote
1answer
158 views

Why the spectral coherence is unity for all frequencies between single-frequency time series and itself

In the example below, I am plotting the coherence between time series and itself. The time series do has one frequency.The coherence magnitude was one for all frequencies. I wonder why it is not zero ...
1
vote
2answers
234 views

Cross-correlation of filtered random processes

I have a wide-sense-stationary (WSS) process $\{x(t)\}$ and two linear filters with impulse functions $h_1$ and $h_2$. Let $\delta(\omega)$ be the power spectrum of $\{x(t)\}$ and $$H_1:\omega\...
0
votes
2answers
46 views

Detecting multi-path propagation when one acoustic signal is dominant

I am sending an acoustic signal from a source to a receiver where there are limited number of paths the signal can travel. I want to detect if there has been multipath propagation or not when one path ...
1
vote
1answer
365 views

Faster Algorithm to convolve/correlate two sparse 1-D signals in python (or any language)

I have two signals which I need to correlate or convolve. Each signal is sampled non-uniformly and the values of the signal I have with me are the timestamp and the magnitude of the signal at that ...
0
votes
0answers
23 views

match a pattern in a stream of bits

I feel my question is somewhat related to this, but I'm not sure how to do what I want. I get transmissions of ~1000 bits at a time, which may be corrupted by noise. To try and infer data from ...
0
votes
1answer
125 views

Correlation between frequency and initial phase estimates using FFT

Why is there a high negative correlation between frequency estimation errors and initial phase estimation errors when measured using FFT? I have a simple code showing this negative correlation. is ...
0
votes
0answers
77 views

Finding recorded sub-signal in the original audio signal

I have the original record of a song, and some fragment of the same song recorded by a microphone. I need to find the time where the fragment is appearing in the original. I have tried to use cross-...
0
votes
1answer
85 views

How to group similar patterns together that are shifted along the x axis?

I have a set of time series plots that are shifted along the x-axis. I am looking for an algorithm using which I can group them together. My end goal is to average them. While reviewing the ...
2
votes
1answer
201 views

Correlation of independent random processes

Suppose $X(t)$ and $Y(t)$ be two independent random processes. Is $E(X(t_1)Y(t_2))$ necessarily zero?
5
votes
1answer
463 views

Maximum cross-correlation coefficient value for time delay estimation

I am using cross-correlation for time delay estimation of two synchronized recordings ($x_1$ and $x_2$) of a fixed sound source from two different locations. I understand that the delay is associated ...
0
votes
0answers
422 views

Cross Correlation as Noise Reduction, is this possible?

If I have two sensor measuring the same signal but from two different locations from the source, and I get two different readings of the signal, each with slightly different noise. Is there a way to ...
2
votes
1answer
210 views

Cross Correlation dimensions

I have been trying to do the cross correlation of two signals, and I am expecting the output to have the same dimensions as the two signals have. However what I am seeing is that the cross correlation ...
0
votes
0answers
25 views

DOA estimation of moving, radiating source in the near-field with nonuniform Doppler shifting

I am trying to estimate the DOA of a radiating source using two passive sensors. In the case of a stationary source, I find the lag $k$ of the maximum in the sample cross-covariance sequence $E \...
0
votes
1answer
113 views

Signals Cross Correlation from Their Power Spectral Densities?

For two real valued signals $f$ and $g$ with their corresponding power spectral densities $|F(k)|^2$ and $|G(k)|^2$ Is there a way to get an intuition of how correlated $f$ and $g$ are just by looking ...
0
votes
1answer
75 views

What is the physical meaning of the cross-spectrum of two signals measured at two locations and different moment?

I am working with steady state pressure field measurement where sound pressure at multiple locations in the field needs to be measured. In my case, more than one microphone existing in the field at ...

1
2
3 4 5
7