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FIR filter phase response at fs/2

0 I am currently building a FIR filter based on frequency sweeping data (0 Hz to Fs/2), i.e., transfer curve in frequency with the sampling rate of Fs. The phase response is shown in the following ...
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3 votes
3 answers
22 views

Use of "Audacity"for teaching undergraduate labs of digital signal processing?

Can we use"audacity"for teaching undergraduate labs/practicals of digital signal processing? or only MATLAB/Octave should be used? Weblink of "audacity" https://www.audacityteam....
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  • 841
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10 views

Interpretation of wavelet trasformation (synchrosqueezing)

I'm working on a dataset of spectroscopies and i'm classifing them by transforming the 1D signal into a 2D one by the library https://github.com/OverLordGoldDragon/ssqueezepy. For istance, consider to ...
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-1 votes
0 answers
18 views

Pathloss calculation in RIS-assisted communication

If we have a path from the Base station to the User via RIS, There are two channels, one is from BS to RIS, and another one is RIS to User. Let's denote the distance between BS to RIS and RIS to User ...
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7 views

Why does EOG (eye EEG) spike and fall back down when you look to one direction?

Why does EOG (eye EEG) first spike and then immediately fall back down when you look to one direction instead if staying spiked and only falling back down when your eyes go back to neutral? From what ...
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-1 votes
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11 views

Inverse Continuous Wavelet Transform off by constant factors

I am implementing a continuous wavelet transform and its inverse using morlet wavelets. When I compute the inverse, the resulting signal is off by some constant factor (but otherwise correct). ...
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0 answers
21 views

Interpolating Filter for Quadrature Detector with one ADC

Single ADC is sampling at 16000 Hz the I and Q outputs of quadrature detector. So each I and Q signal is sampled at 8000 Hz, with phase offset 90 degrees between them. Bandwidth of interest is 3400 Hz....
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1 vote
0 answers
16 views

How can a common trends be detected and filtered from multiple spectra data?

I'm looking at spectral data collected through Cavity ring-down spectroscopy. I'm comparing a few samples of similar analytes and expect slightly different peak heights and trends. However, there are ...
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1 vote
1 answer
29 views

FFT Artifacts and their cause beyond frequency resolution

I am trying to work through an issue with an FFT for audio : I have no spectral leakage while playing back audio, but the moment I change or zero out a value in any of the FFT bins, artifacts are ...
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  • 11
2 votes
1 answer
28 views

FMCW Transmit Signal and Fly-back Effect

I am studying a thesis about nonlinearities in the transmit signal and it mentions the following: The first 2,500 samples, which correspond to the Tmax of each of each sweep period and are affected ...
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1 answer
234 views

Why do some signals have "DC component" whilst others don't?

I am analyzing a series of oscillating data of items that gradually become less "floppy"/oscillatory and I have observed that those items that are less floppy/oscillatory tend to have, what ...
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1 vote
0 answers
17 views

How to determine the permutation parameters for a Turbo Code Interleaver?

In the 2004 paper Designing good permutations for turbo codes: towards a single model it is mentioned you mention that : "turbo code permutation of DVB-RCS [5] and DVB-RCT [6] standards, which ...
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  • 962
1 vote
1 answer
28 views

Spreading sequence in DSSS [closed]

In DSSS, the spreading sequence is known only to the receiver and the transmitter. But for example, if we consider a spreading sequence built around a certain signal known only to the receiver and not ...
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0 votes
1 answer
26 views

Expressing mathematically the number of real addition operation for a vector after dividing it

I assume I have the length of such vector $y$ is $N$. In the first time I divide that vector into two columns and then sum them point-wise summation. The second time, I divide the same vector $y$ ...
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  • 593
1 vote
2 answers
82 views

Basics of interpolation: is filter or upsample first?

I am studying interpolation filter. I have thought if we speak about interpolation, we filter and then upsample a signal. BUT In an article, Interpolation (Digital Filter Design Toolkit, is given a ...
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  • 69
1 vote
0 answers
20 views

Stability analysis of hybrid discrete-continuous systems

I'm trying to derive the overall state-space system model for a hybrid system, in order to plot its eigenvalues. The system is shown as follows: Which is originally from this paper: Modeling and ...
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1 vote
0 answers
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How do I convert the Amplitude from Power/Amplitude spectral density?

I recently started working on PSD of seismic signals. PSD signal can be expressed in 2 ways. One in ($PSD=g^2/Hz$) and other in $PSD=((meter/sec.^2)^2/Hz)$ and $ASD = \sqrt(PSD)$. More details have ...
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  • 21
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1 answer
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Interpolate & sample period GNU Radio

I've a little question regarding interpolation in GNU Radio: I'd like to do an interpolation (by a factor of 2) and be able to change the sampling period of the samples interpolated but im having a ...
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  • 1
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2 answers
67 views

Help Understanding FFT Plot?

I want to analyze FFT and Harmonics of my signal. As a proof of concept I tested FFT against standard signal. I am unable to understand why the frequency output is going to -1. Shouldn't it be +1 at <...
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6 votes
2 answers
598 views

Downsample a signal by a non-integer factor

I have a signal with a sample rate of 8.9286 MHz and I want to downsample it to 500 kHz. Since 8.9286 is not an integer multiple of 0.5 I can't simply decimate. Which downsample techniques are ...
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0 votes
1 answer
33 views

Demodulate qpsk with gnu radio

I'm trying to demodulate a qpsk signal with gnu radio. The signal is from the meteor satellite on 137MHz https://www.sigidwiki.com/wiki/Low_Rate_Picture_Transmission_(LRPT). I recorded the signal with ...
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0 votes
1 answer
35 views

What is the complexity of multiplication a real matrix with real vector

I have a real matrix $Z$ which is following the form as following: $Z = \begin{bmatrix} x_1& 0& 0& 0& 0& 0& 0& 0\\ 0& x_2& 0& 0& 0 & 0&...
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  • 593
3 votes
0 answers
33 views

Improving the intuition for the 2d fourier transform

As far as I understand, the 2d fourier transform is calculated as following: ...
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  • 31
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0 answers
32 views

Time derivative affect on the information entropy and compressed signal size

I have found out that the entropy of the measured signal (int16), is slightly larger (10%-5%) than the entropy of the signal's time derivative. Intuitively, this makes sense in the case of a ...
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0 votes
0 answers
36 views

Imitate noise audio file with math function

Is it possible to reverse engineer a short white noise audio file and imitate it with a function instead? The file doesn't contain pure white noise, there has been EQ applied to it, also some ...
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0 votes
0 answers
19 views

How to add quantization noise (SQNR) to thermal noise (SNR) in a total value?

How can I add the BAQ (Block Adaptive Quantizer) compression noise to the input SNR? In the end is a quantization noise to be added to a thermal noise. I got the following formulation, but I dont ...
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  • 11
2 votes
2 answers
30 views

How does the sample rate work on an SDR?

How can an SDR, which has a sample rate of about 32MHz record signals with a frequency of 1GHz? Shouldn't the sample rate be at least two times as high as the frequency or am i missing something?
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  • 21
1 vote
1 answer
35 views

Problems designing a notch filter based on allpass in MATLAB

I have to design a notch filter based on an allpass but when I plot the resulting filter in MATLAB it does not fit my specification. I'll provide you with some background. The filter has the following ...
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2 votes
2 answers
46 views

Metric for image sharpness?

Suppose I have a blurry image: a photo convolved with a gaussian blur kernel of unknown sigma. I would want to deconvolve the blurry image using several gaussian kernels (with different sigmas). Is ...
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3 votes
1 answer
67 views

Can we recover $|X(k)|$, given $|x(n)|$?

Given a complex vector $x[n]$, we can find the magnitudes of the spectrum by computing: $X_m[k] = |X[k]| = |FFT[x]|$ This involves performing a complex FFT and computing the absolute value of the ...
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  • 55
2 votes
1 answer
29 views

Image warping with heat map that "pulls" on pixels

I am looking for an efficient image warping function $$f: (\text{image}\in \mathbb R ^{M\times N\times3}, \text{heatMap} \in \mathbb R ^{M\times N}) \to \text{warpedImage} \in \mathbb R ^{M\times N\...
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  • 123
3 votes
1 answer
83 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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  • 152
0 votes
2 answers
30 views

$\min(\{Z_i\})$ for non-i.i.d. random variables $Z_i$ the same as for i.i.d.?

My question is with reference to wireless communication. There are $N$ independent and identically distributed random channels i.e., $Z_i \in \{ Z_1, Z_2,\ldots, Z_N\}$ with PDFs $f_{Z_i}(z)$ ordered ...
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  • 17
1 vote
2 answers
37 views

Random gaussian noise estimation from a given trajectory

I wish to estimate the noise of given trajectory from a measurement (data which is provided). I consider that the noise is random gaussian noise. I add here examples of two trajectories, one of the ...
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  • 111
1 vote
1 answer
33 views

RRC filter has massive impulse response

I am trying to pass a BPSK signal through a root-raised cosine filter in Octave. To do this, I convolve the signal with the impulse response of an RRC filter, defined as follows (source): The BPSK ...
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1 vote
1 answer
44 views

How to Calculate Frequency "X values" from a FFT/DFT Transformation

First of all I am totally new to the DSP field and I have no background in it whatsoever, but my work in biology has led me to data that would greatly benefit from DSP. Any answers devoid of specific ...
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0 votes
1 answer
57 views

(Python - Scipy - Wave files) Can a float signal be written with values higher than 1?

While developing an application, I noticed strange behaviour while using scipy.io.wavfile to write audio files. The documentation says that floating-point data is written within a range between -1 and ...
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0 votes
0 answers
30 views

What does the following structure mean and how to implement this structure in matlab?

Looking forward to explaining what this structure means, and the relationship between the two structures. Paper: An Efficient Spur-Aliasing-Free Spectral Calibration Technique in Time-Interleaved ADCs
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22 views

Research on SDR security Gnu Radio and legal transmission with filters

In fact, I am doing research around SDR and possible dangers. Then I stumbled upon the most well known "replay attack". Via Black hills, I came across the following diagram in gnuradio: The ...
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0 votes
0 answers
11 views

Upsampling after S/P convertor in MSK modulation

I have found this post "implementation a S/P conversion: different length / in Matlab" In the given implementation, Tsym = 2*ovs. ...
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  • 69
0 votes
1 answer
48 views

How to create an ideal sine wave that will be the best fit for given sine wave with noise and distortion

I have a sine waveform that is a result of simulation. This is always single tone with a constant offset, but with distortion and noise and may have some jitter: $$s[k] = A\sin\left(2\pi \frac{f}{f_\...
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  • 261
0 votes
0 answers
10 views

GMSK Demodulator in Simulink

I am trying to implement a GMSK transmission chain, over AWGN. I tried both the precoded GMSK and the GMSK without precoding, and in principle with the precoding we should see the BER halved. However ...
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  • 13
0 votes
0 answers
38 views

Equivalence between two PSDs

I'm very very new to these topics, as I started last week my master thesis (mechanical engineering) on something related to vibration analysis. From an engine RPM distribution and the acceleration ...
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1 vote
0 answers
20 views

Stationarity Test on Dataset

I have a nice and clean noise signal sampled at a fixed rate for several hours. When I calculate the PSD I see it's pure flicker noise. But I don't know much about the process. I've seen some ...
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  • 61
0 votes
1 answer
25 views

Order statistics: always applicable tool in wireless communication?

I have seen few papers where generalized order statistics is used to obtain statistics of the instantaneous SNR. "Performance analysis of monostatic multi-tag backscatter systems with general ...
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  • 17
1 vote
1 answer
27 views

Inverse continuous wavelet transform output has significant error in magnitude and phase

For the inverse continuous wavelet transform, I am using a for-loop which runs through each frequency. At each frequency, I convolve the corresponding morlet wavelet with the signal at that frequency, ...
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0 votes
0 answers
25 views

A python-based implementation of time-frequency block thresholding for audio signals?

I'm looking for a python implementation of the block-thresholding algorithm introduced in this classic paper. I've been searching a while but I couldn't find it :(. There is of course a Matlab ...
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  • 1
1 vote
1 answer
36 views

Understanding Pathloss and latency

In my class on wireless communication, I came across the following sentence: The round trip path-loss can be defined to include aspects such as attenuation and/or latency etc Hence I am looking for ...
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  • 17
1 vote
0 answers
52 views

Meaning of "standard deviation noises of wavelet coefficients"

I am currently working on a research project based on the paper titled A deep learning approach for anomaly detection based on SAE and LSTM in mechanical equipment. The paper uses data in the acoustic ...
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0 votes
0 answers
17 views

How to proprely rescale measured channel statistics

I’ve got a vector of measured instantaneous power at the receiver side. The vector is normalized in a way that the average is 1W. Now I would like to apply this vector to my channel model to check if ...
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