Questions tagged [array-signal-processing]

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1 answer
41 views

How to get a single point of the rising edge of a square wave in relation to its time?

I am trying to get data from only 1 point of each rising edge and trying to relate it to 1 point of the sin wave at the same time. Ideally, the middle of the rising edge is where I want the sin wave ...
2 votes
1 answer
62 views

Having problems with GMSK modulation

I'm trying to modulate array of bits with GMSK modulation with BT=0.3 . What I'm doing is making O-QPSK modulation for given bits, then applying Gaussian filter on I and Q arrays and after that ...
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2 votes
1 answer
59 views

Determining location of moved sensor in near field array processing

I have a situation where a linear array of sensors monitoring near field sources has had one of the sensors bumped so that the sensor position is off by a smallish amount and is not in its original ...
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3 votes
1 answer
90 views

Crash course on Sonar

I have some experience in Signal processing and a lot more in solving numerically the electromagnetic field integral equations using Matlab and C++. Now I am curious about the Sonar (e.g., underwater) ...
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0 votes
0 answers
73 views

How to calculate Diffential Entropy (DE) in Python?

I am working with a data which is actually the popular EEG data called DEAP. It basically is a 3D array of size (40, 40, 8064) and here is the link to the official dataset website: https://www.eecs....
3 votes
1 answer
81 views

How does SciPy's Welch function change the shape of the data?

I am working with some time series data with a shape of 8064. The data is actually the popular EEG data called DEAP. It basically is a 3D array of size (40, 40, 8064) and here is the link to the ...
4 votes
1 answer
144 views

Estimation of the attenuation of two waves on a linear sensor array

Context and objective I am trying to estimate the attenuation coefficients ($\alpha_u$ and $\alpha_v$) of two waves ($\overrightarrow{u}$ and $\overrightarrow{v}$). These waves propagate on a linear ...
3 votes
1 answer
136 views

MUSIC implementation in Pyroomacoustics library

I am currently using the multiple signal classification (MUSIC) algorithm provided by the Pyroomacoustics library in order to estimate direction of arrival angles and it works pretty well for both ...
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1 vote
1 answer
28 views

Basis Pursuit Denoising (BPDN) algorithm for Direction of Arrival Estimation

I am working on Compressive sensing algorithms for DOA estimation. Can i get any references for writing BPDN code in MATLAB.
1 vote
2 answers
58 views

Which of an array's contiguous subarrays is an algorithm best applied to?

A function $f$ accepts two equally-long arrays $A$ and $B$ as input, and returns a real number $s$ such that the root mean square of $A-sB$ is minimal. I'm hoping to come up with a better-than-brute-...
8 votes
1 answer
184 views

MUSIC Algorithm for Direction of Arrival (DOA) in Acoustic Signals

I have seen multiple reviews of the MUSIC algorithm for the estimation of DOA. Most of those reviews consider a complex signal input with a complex steering vector. So, how do I implement this ...
0 votes
0 answers
115 views

What is going wrong with the plot of 2D spatial spectrum at a specific frequency?

I've a set of 09 sensors in the following arrangement and the script for the sensor positions as follows: ...
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0 votes
0 answers
20 views

pan tompkins algorithm and thresholding

so iam trying to understand the pan tompkins algorithm for QRS detection and i was curious about where did they deduce this threshold formula : Threshold $I_{l} = NPKI + 0.25 \left( SPKI - NPKI \right)...
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0 votes
0 answers
17 views

How do I make a graph of pseudo frequency vs. time. in ssqueezepy?

How do I make the y axis in psuedo-frequency? ...
2 votes
1 answer
40 views

pan-tompkins algorithm

The difference equation of the differentiator used in pan-tompkins algorithm is as follows : ( a five-point derivative) $$ y \left( n T \right) = \frac{1}{8} T \left[-x \left(nT - 2 T \right) - 2x \...
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1 vote
1 answer
48 views

DSP based phase shifting in Phased Array systems

Is there a downside to doing phase shifting at basedband in the DSP section of phased Array systems? I suppose you trade off analog components for digital which may be more costly but I suspect modern ...
1 vote
1 answer
29 views

magnitude spectrum

I have an ECQ signal of 360 Hz sampling frequency. I used an FFT to extract the frequency spectrum of my signal. Now I don't know exactly how to interpret this plot. How can I know the noise from ...
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1 vote
1 answer
70 views

How to perform the 2d Vector Antenna in LabView for MUSIC Algroithm

I have 1 transmitted channel and 4 receiving channels on Uniform Linear Array (ULA) and I am using the MUSIC algorithm to determine the AoA of the incoming signals in LabView. Now I want to use the 2D ...
4 votes
2 answers
148 views

MUSIC Algorithm in LabView not Working Well

I am working on performing the MUSIC Algorithm in LabView. The hardware testbed includes four phase-locked receiving channels and a coherent single-channel transmitter (first I will verify the MUSIC ...
1 vote
1 answer
47 views

Simulation of Discrete Inverse Fourier Transform of an array in Python

So I have a simulation to get Fourier Transform of an given array. This is my Python code to get Fourier Transform ...
2 votes
4 answers
226 views

Finding the mode of propagation of a progressive wave and the velocity of that mode

Injecting a sinusoid say, $Z = A \sin(k_x X + k_y Y - \omega t)$, $K = 2 \pi f/c$, for example, assume $f = 10$ Hz or $50$ Hz, and $c = 50$ m/s, now if I draw the 2D K-space plot with the following ...
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3 votes
0 answers
71 views

Direction-of-Arrival estimates clustered at specific angles

I am having an issue which I cannot understand completely. I am working on a simple project where I am testing various algorithms from the family of the Generalised Cross Correlation [GCC] for ...
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0 votes
0 answers
30 views

pattern recognition with some features in time series data

I am trying to capture peaks in a time series data which has some predefined feature. Here is a snapshot of time-series data (Time series data with peaks) In this time-series I want to detect peaks ...
1 vote
3 answers
134 views

Convert a list of values and times into an audio file

I have two pandas dataframe, one with time in seconds and one with the actual audio data (values from -1 to 1). The audio data points are not equidistant, this why I need the list of time in seconds. ...
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1 vote
0 answers
58 views

What are some good examples of applications of Circular Convolution in Signal Processing and Image Processing?

I have derived the circular convolution property for an affine Fractional Fourier Transform and I need to work on an application for my research. Any idea?
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0 votes
0 answers
43 views

I have two signals, recorded from the same device. How do I standardize/normalise them?

I essentially have two signals X and Y, recorded with PPG devices. These have been filtered already. I want to standardize(z-score) or min-max scale them but I don't know if I should do this on each ...
1 vote
2 answers
79 views

Discrete Wavelet Transform (DWT) and wavelet family

I have just started reading about wavelets for a data compression problem that I want to perform. I am reading about Discrete Wavelet Transform (DWT) but I can't understand where the wavelet family ...
2 votes
3 answers
159 views

What does the intensity values on wavelet transform mean? Amplitude or power?

So when applying wavelet transform, we get a 2d plot. Each point in that 2d plot has a color, showing intensity of something. But I cannot understand if it is an amplitude or power?
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0 votes
1 answer
74 views

Can FFT tells us existance of same frequencies with different phases?

So I know that applying FFT on a time-domain signal, shows which frequency components exists and what amplitudes each frequency signal has. My question is, suppose the signal contains same frequency ...
  • 149
0 votes
1 answer
217 views

Extracting different frequency bands (alpha, beta, gamma) from MEG source estimated data

I have a dataset that consists of source estimated data of MEG brain signals. I need to extract the different frequency band features (i.e., alpha, beta, gamma, etc) from them. What steps/procedure ...
  • 149
0 votes
1 answer
57 views

Calculating power of brain signals

I have a dataset that contains EEG (or MEG) recordings of brain signals during some cognitive tasks. Each row, shows the source estimates of neurons in a particular region. source estimate contains ...
  • 149
0 votes
2 answers
587 views

Why does my amplitude change upon inverse Fourier Transform when I am only randomizing the phase of the fourier transform using Python numpy?

I am trying to make a surrogate time series of a discrete data series using python, basically I wish to keep the amplitude same and change the frequency I take a Fourier Transform of the data I ...
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2 votes
2 answers
239 views

How to reconstruct the signal using overlapping frames in MATLAB

I understand that we can use the buffer function in matlab to split a long signal into overlapping frames. But is there any functions that we can use to put the ...
  • 21
3 votes
2 answers
186 views

Why do we need to estimate eigenvalues?

I am not working in signal processing field, but recently I happen to read a paper which estimates source numbers using Gerschgorin radii, and I feel kind of confused about why we need to estimate ...
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-1 votes
1 answer
64 views

Visualise/compare numpy arrays from Matlab/Octave to matplotlib

I'm new to python and matplotlib, and I'd like to visualise / compare 3 mfcc files stored as numpy arrays in txt format. I have the Octave code below, and I'd like to know how it can be done using ...
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0 votes
0 answers
119 views

Signal-to-Noise ratio of multivariate stochastic process from Correlation Matrix

I'm not in signal processing, I'm from an another discipline. I've derived a simple result which I presume must be well known in SP and I'd like to know whether there's a paper or textbook that has it ...
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1 vote
1 answer
231 views

a neural network approach for FIR filter

I am trying to write a code for a neural network to do the digital filtering on some signals. Is there any neural network model for digital filtering?
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1 vote
0 answers
76 views

Spatial moving average in array antenna processing

In array processing the theoretical spatial response of the array is calculated by doing DFT on sensor locations for some assumed wave number (1/wavelength). The figures below shows the sensor ...
0 votes
1 answer
141 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 ...
0 votes
0 answers
62 views

What is Ad-hoc microphone array?

I have stumbled upon this term in many papers, though no one bothers to elaborate. Is this the case where I do not have prior knowledge of the array structure? or otherwise is it the number of ...
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0 votes
1 answer
90 views

Discrete Signal Windowing

How do we apply windowing of 50% (4 samples) to a discrete signal with the odd number of values as 1234567? Is it done as: ...
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3 votes
2 answers
1k views

MUltiple SIgnal Classification (MUSIC) Implementation

I have a linear 4 element antenna array currently in my design, I am able to obtain the I/Q data from each antenna. Now I am trying to implement the MUSIC algorithm to obtain the AoA (Angle of Arrival)...
0 votes
0 answers
26 views

When does the narrowband model in array processing fail?

I am not sure that I understand well the narrowband assumption in array processing. I wonder how it simplifies the model and what would change if not assumed. Also, what will happen if I apply the ...
0 votes
0 answers
28 views

Calculate the percentage of accuracy with which user made the assigned sound

I want to design a web-app for my cousin who is 2 years of age in which i have implemented a functionality in which when an image is clicked some sound gets played and the user has to make the same ...
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0 votes
1 answer
427 views

Zero peaks in fft data even after subtracting mean

I have a time series sensor data. It is for a period of 24 hours sampled every minute (so in total 1440 data points per day). I did a fft on this to see what are the dominant frequencies. But what I ...
  • 1
0 votes
1 answer
3k views

Python code for QPSK modulator [closed]

Have any of you done anything like QPSK Modulation in python? I am in the middle of it and having problems in setting up bits? like odd and even bits. Have you got any idea? Regards, Sam
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0 votes
1 answer
134 views

Question about eigendecomposition, signal subspace and their properties

Lately, I am readig a paper titled A Subspace Method for Estimating Sensor Gains and Phases. In it, it is mentioned: There are $m$ sensors in the array, $n$ known narrowband far-field signals($m \...
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2 votes
1 answer
249 views

Source Localization with the BLUE Estimator

I'm trying to implement BLUE estimator in MATLAB for source localization and after my research I've come up with a theoretical example in Steven Kay's "Fundamentals of Statistical Signal Processing: ...
1 vote
0 answers
58 views

Sign of manifold vectors in monostatic phased-array radar

I am reading some notes where the impulse response of phased-array to is given by; $$ \beta S(\theta, \phi) \bar{S}^H(\theta, \phi) \cdot \delta(t-\tau) $$ where \begin{align} \bar{S}(\theta, \phi)...
  • 11
0 votes
1 answer
387 views

Detect when signal starts oscillating

I have a signal which consists of oscillations riding on square waves as shown in the image below. I wish to detect the time at which oscillatory events occur (as shown by the red star). Each square ...