# All Questions

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26 views

### Beamforming but only for total power?

Is there a method to speed up beam-forming if you only care about the total power in a given direction, or total power in frequency groups? I've googled this, and can't find anything. My intuition ...
19 views

### Audio mixer (VDSM01) to plug tv and computer on a single speaker

I have a set of speakers which are plugged through jack 3.5 to my TV. When I want to use the speakers on my computer I have to unplug the cable from TV and plug it on computer and vice versa. I would ...
11 views

### Size filtering on binary images

I have noisy images from which I extract the contours using OpencCV's findCountours, which performs binarization internally. This results in innumerable small ...
9 views

### Waveform screenshot to DAT file

Let's say that we have a screenshot of a waveform we're trying to analyze, is there any software that can convert the screenshot to a DAT file or any other format that can be exploited on Matlab?
59 views

### Understanding the phase in DFT

Although using regularly the FFT algorithm to compute DFTs, I don't really understand how the phase part works. e.g. in Matlab: ...
33 views

### On generalizing Gabor-Heisenberg uncertainty in a noisy environment

The Gabor-Heisenberg uncertainty represents the fundamental limit of time and frequency resolution one can extract from a signal. $\sigma_t \sigma_f \geq \frac{1}{4\pi}$ My question is: what happen ...
12 views

### Matlab code for Hilbert marginal spectrum

I am looking for a Matlab code for Hilbert Marginal spectrum. There is no information on Matlab official website. Please help.
19 views

### Generating virtual signals based on real ones

The project I'm working on requires collecting signals from different experiments and developing algorithms to extract certain information from these signals. The problem is I got to collect very few ...
20 views

### Over-the-air (OTA) BER measurement

I'm in the process of evaluating BER performance for a GNU Radio BPSK receiver. The setup for the experiment is illustrated below. Using a spectrum analyzer just before the USRP, the average channel ...
16 views

### Power and Energy of an Audio file

I have a question about calculating the power and Energy of an audio recording. I have imported a waveform of an audio recording in WAV format into Matlab and then calculated the energy and power in ...
33 views

### Why does the flat part of the BER curve appear after the Viterbi decoder (MatLab)?

I am trying to implement convolutional codes according to this MathWorks example in MatLab 2014a. ...
33 views

### Convolution Theorem: Hamming Window on a Time Series and Fourier Domain

If we have a set of time series data, y, consisting of 100 data points. One can apply a N (odd) Hamming window as a weighted moving average to decrease the noise. Say, if we choose 7 point Hamming ...
33 views

### Which Machine or deep learning algorithm is appropriate of this issue?

Suppose I have $n$ features as $Y$ = ($y_1 , y_2 ...., y_n$), and a matrix of $J$ of dimension $M$x$N$, one feature of $Y$ is selected randomly to be convoluted with one random column of $J$ resulting ...
6 views

### Morse / Morlet wavelet relationship?

Does anybody know what the relationship between Morse and (complex) Morlet wavelets are? I'm looking at images in papers about the Morse, and it looks like a Morlet to me. Is the Morse a ...
58 views

### Does convolution violate duality of a Fourier Transform

Duality says that if $$x(t) \iff X(\omega)$$ then $$X(t) \iff 2\pi \cdot x(-\omega)$$ Given that $$f(t)\circledast g(t) \iff F(\omega)G(\omega)$$ By duality, shouldn't that imply that  f(t)...
12 views

### What is the difference between positive matrix coefficients and negative matrix coefficients of an audio?

I have turned an audio file into an one dimensional array by using audioread function in matlab and found several positive and negative fractional coefficient values.What is the basic difference of ...
27 views

### (FFT) Is it good practice to ignore each bin's phase when characterizing a signal

I have been recently working with the FFT and realized that each frequency within a bin corresponds to a phase. I understand why a phase that corresponds to each frequency is needed because it allows ...
17 views

### Aliased Signal's Frequency

So I have an incoming signal of 137.9 MHz and a sampling frequency of 1.4 MHz. Once sampled how do I calculate the aliased signal's new frequency? Bandwidth is 38 kHz with a subcarrier of 2400 Hz if ...
4 views

### Signal Header:Physical Min is not less than Physical Max- after opening EDF file on the viewer

Whenever I open an EDF file on the Case Western Research University's EDF Viewer Application, I get a Scaling Warning-"Signal Header:Physical Min is not less than the Physical Max ". I am reading ...
25 views

### What does imaginary Component of a bin's phase in the Fourier Transform mean?

I have been recently working with the FFT and realized that each frequency within a bin corresponds to a phase. This concept I have no problem with because if you wanted to construct the summation of ...
11 views

### How can single low-resolution have multiple high-resolution versions?

I'm trying to prove the fact that the super-resolution problem is ill-posed problem. As having a single low-resolution image we can generate multiple high-resolution images. which also known by ...
17 views

### psd in matlab, problem with the coefficient $\frac{1}{2\pi}$

Using the fft to mimic the Fourier Transform I have this question. The definition that I use for the PSD $S(f)$ is: $S(f)=\frac{1}{2\pi}\int_{\infty}^{\infty}exp(-i\tau2\pi f)r(\tau)d\tau$ where r(t)...
18 views

### Calculation of PSD using Hamming Window

I have 600000 time domain Data. I want to calculate the psd using that data. But I want to use hamming window to my data set and overlapping them to get a smooth psd vs. frequency graph. I need a ...
10 views

### What is the significance of y-axis in Lomb-Scargle Periodogram?

What does the y-axis of Lomb-Scargle periodogram represent? Periodogram obtained by Fourier transform contains information about the original data's amplitude, but the so-called "Lomb-Scargle power" ...
20 views

### Classifier for detecting abnormal noise using FFT

As a simple machine learning application for quality evaluation, I want to detect abnormal sound in a product. A good product would make a signature humming sound, a bad product might make noises due ...
18 views

### Help to identify this impulse/autocovariance

I have attached a picture of an autocovariance over a single lag. To my (inexperienced) eye this looks like some kind of impulse response but I am unable to identify the function. The picture is taken ...
39 views

11 views

### Extract feature points and visualize on 3d Mesh

I'm Coding with python, I have a 3d Model mesh, and I'm trying to get features and descriptors So I was able to get Zernike moments using mahotas library which gives a vector of data, I have to ...
36 views

### What is matched filter in QPSK signal?

Consider we have received a QPSK signal. We than make I (In phase) and Q (quadrature component) which I understand is nothing but multiplying the received signal by the cos(2*pi*f) and -sin(2*pi*f) ...
63 views
+50

### Number of microphone limitation for Spherical Harmonics based DOA estimation

I am following this book "Theory and Applications of Spherical Microphone Array Processing", as well as this paper on DOA estimation "Eigenbeam-ESPRIT for DOA-Vector Estimation". My dataset is ...
### What does $I_{seg}$ in 3GPP TS 38.212 version 15.2.0 Release 15 represents?
I'm working on 5G NR, whereby on reading Code block segmentation and code block CRC attachment given in Subclause 5.2.1 of 3GPP TS 38.212 version 15.2.0 Release 15. What does $I_{seg}$ represent?