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5 views

Find LF component of AM signal

I'm trying to figure out how to find the low frequency component of an AM-signal when I have regained the carrier. So the signal is: $$U_{AM} = 2[3+0.4cos(2\pi\cdot2\cdot 10^3\cdot t)]\cdot sin(2\pi\...
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0answers
9 views

Implementation QPSK modulation code in MATLAB

I am trying to implement modulation schemes for a codebook. I have written smth for QPSK. I have started with Initialization an initial value as "ones(nm,1) exp(i*pi/4)" then i have used "while" ...
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1answer
11 views

Definition of MIMO (Multi-input Multi-output ),does this output mean antenna or transmitter?

I want to ask the definition of MIMO(Multi-input Multi-output ) If there are one transmitter and one receiver,each of them has $N$ antennas,$N >1$. So i can say it is a MIMO system. But if now i ...
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2answers
38 views

DCT vs DFT why do we need/want phase?

Why do we use complex exponentials in the Fourier transform, why do we want the phase part? As opposed to in DCT where there is no phase and only magnitude? Moreover, what does this phase concretely ...
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1answer
27 views

FFT and Power Spectrum Normalization

On many websites, including MathWorks, it was suggested to normalize the fft spectrum (MATLAB or numpy) by dividing it by the total number of samples ($N$). For a sinusoidal signal, for example: $$x(...
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1answer
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 ...
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0answers
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 ...
1
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0answers
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 ...
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0answers
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?
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2answers
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: ...
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1answer
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 ...
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0answers
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.
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0answers
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 ...
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0answers
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 ...
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1answer
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 ...
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1answer
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. ...
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1answer
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 ...
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1answer
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 ...
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0answers
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 ...
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2answers
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)...
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1answer
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 ...
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2answers
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 ...
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0answers
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 ...
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0answers
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 ...
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1answer
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 ...
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0answers
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 ...
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1answer
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)...
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0answers
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 ...
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0answers
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" ...
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0answers
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 ...
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0answers
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 ...
1
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1answer
39 views

What is the effect on Hilbert transform of signal after multiplication by sinusoid?

Question : Find Hilbert transform of $[u(t-a)-u(t-b)]\cos2\pi f_{0}t\\\\$ such that $\\0<a<b$ my attempt: we know Hilbert transform of $[u(t-a)-u(t-b)]\xrightarrow{\mathcal H} \dfrac{1}{\pi}\...
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1answer
33 views

Sampling rate issue in microcontroller

I am using 3 axis LIS2D12H accelerometer interfaced with NRF51832 with SPI interface. The sensor has sampling rate from 1 HZ to 5.376 KHz which is happening at sensor only. I am taking sensor data at ...
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1answer
28 views

How should I remove obvious anomalies from spectral data?

I'm working with raman spectra and it seems that our spectrometer produces some anomalies at very specific wave numbers and I'm looking to remove them from the dataset. Here's a picture of 27 spectra ...
1
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1answer
30 views

How can I detect the tree rings?

I'm looking for the way to detect the tree rings automatically in the wood dist image. Using the matlab, I have removed the background, and binarized the image. How can I detect the white and black ...
0
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1answer
61 views

Frequency Domain Interpolation: Convolution with Sinc Function

I am reading a paper, and I came across the following definition of sinc interpolation. Warning. I don't have a strong background in signal processing. Also, I have no clue what that bar on $\bar{F}$ ...
1
vote
1answer
39 views

reference parseval theorem limited signal

some days ago I asked here parseval for a continuos but limited signal if the Parseval can be applied for limited signal. Can you recommend me a book or a paper that I can use as reference for this? ...
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0answers
22 views

Multiband undersampling

In Practical Signal Processing (Marc Owen), an exercise explore the topic of undersampling: [...] Suppose you know that an audio signal is a sine wave with a frequency that might be in one of two ...
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0answers
10 views

temporal smoothing: FWHM of Gaussian kernel vs. window length of moving average

Suppose in one case I convolve Gaussian kernel with FWHM=10 samples. I would like to compare the result with moving average. My question: should I take the moving average window also 10 samples? In ...
0
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0answers
18 views

Moving noise floor spectrum after decimation

Currently I am working in a spectrometer with a stage of decimation previous the fft. In particular I am decimating with a factor of 16 in two stages of 4 each one. I attach a diagram of the model (I'...
1
vote
3answers
37 views

Why bit rate is same in a lower frequency spectrum and higher spectrum?

If there is a spectrum between 0 Mhz - 1 Mhz, bandwidth would be 1 Mhz here and for example with baseband we can send 2000 bps. What I can't understand is if spectrum is 5-6 Mhz instead of 0 - 1 Mhz, ...
2
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5answers
554 views

Clarification on defining FFT bin sizes

When reconstructing the frequency domain for an FFT, what is the most self-consistent way to do this -- i.e. how is it best to define the bin width, $\Delta f$? For example, previously I thought it a ...
1
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0answers
45 views

low-pass filter and the sharp cut-off filter

are the low-pass filter and the sharp cut-off filter the same thing?? Here there is the definition of sharp cut-off filter https://en.wikipedia.org/wiki/Filter_(large_eddy_simulation) . I tried to ...
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0answers
8 views

Questions about Optical Flow implementations

I have some doubts related to some of the optical flow implementations. How to compute angular error for optical flow algorithms? I know the formula for computing, $\theta=\arccos(\vec{v}_c\cdot\vec{...
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0answers
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 ...
0
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1answer
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) ...
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2answers
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 ...
0
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0answers
12 views

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?
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1answer
34 views

Unexpected frequency components found in Periodogram

I am trying to make sense of Digital Signal Processing with the help of R language. So, the issue came up when I tried to create a periodogram for a simple sine wave. The regular periodogram shows 2 ...

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