Questions tagged [signal-analysis]

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117 views

CIC Filter implementation for Normalized Correlation

This is a follow-on to the original post ... I am trying to implement real-time correlation of two signals. I noticed the CIC Filter discussion here: How to find correlation/cross-correlation of two ...
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1answer
33 views

Converting IQ to RF data

I appreciate any help: I wanna convert IQ data to its RF data, representing an image. The center frequency and sampling rate are available. What I do is: First I do up-sampling in MATLAB by applying ...
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0answers
34 views

IQ to RF conversion [closed]

I appreciate any help: I wanna convert IQ data to its RF data, representing an image. The center frequency and sampling rate are available. What I do is: First I do up-sampling in MATLAB by ...
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1answer
62 views

Continuous wavelet transform

Continuous wavelet transformation has been quite widely used for various applications. Most of the papers that I found were using CWT for non-stationary signals. Can we use CWT for stationary signal ...
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31 views

Frequency contour detection in spectrogram

I have an image of a spectrogram and I wish to detect the tracks/contours of prominent frequencies present in the spectrogram. In the end, I want to be able to get various prominent curves from the ...
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1answer
48 views

Maintain constant total amplitude of sum of sines

Given a set of N sine waves, each with their own amplitude and frequency, is there a straightforward way to select their phases such that the sum over all sines maintains a constant amplitude, given ...
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0answers
27 views

Why my result from FFT which is negative frequencies are different from positive frequencies

I am trying to analyze a signal from monkey brain by applying FFT on the signal. By using numpy.fft.fft function to perform Fourier Transform on raw signal, I got the power of frequencies in the ...
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2answers
124 views

Signals - question due to sampling

I don't have an idea how to start it. Help pls :) $$m = z(t) + \frac{\operatorname{Sa}(t-T)}{4}$$ We have some signal $z(t)=\left(\operatorname{Sa}(\frac{t}{T})\right)^2$. How often the m signal ...
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1answer
260 views

Power Spectral Density of discrete White Gaussian Noise defined with variance and sampling interval

From Creighton and Anderson Chapter 7 on Gravitational Wave data analysis: Please explain where the delta t and the limit came from in this derivation.
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1answer
58 views

Conversion from counts to dB

I have a sound signal, recorded by a hydrophone, which units are counts. I would like to convert the counts into dB re uPa (Decibels relative to microPascals), is that possible?
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0answers
23 views

Flicker Frequency for taking snapshot of monitor [closed]

When a snapshot of a monitor with refresh rate 60 Hz is taken with a camera with rolling shutter config operating at 30 FPS, what is the expected flicker frequency in the resultant image? I took ...
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10 views

EEG signal dataset info

So I wanted to use pre processing on EEG data obtained from BCI competition 2005 dataset iiia which is a multiclass dataset. This data has lots of info on it but i cant seem to obtain/get data other ...
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2answers
180 views

Significance of sequency ordering in Walsh-Hadamard matrices

So I've been doing some reading into Hadamard and related matrices (Slant, Walsh, , and have observed that there are three typical "orderings" of the rows based on various criterion. E.g. "Natural", "...
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1answer
52 views

Problem in verifying zero blocking property of a zero of a multiple input multiple output system

I have a multiple input multiple output control system, and in particular a two inputs two outputs system. I want to find the zero state direction and the zero input direction of the system, which has ...
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1answer
33 views

Hand written DFT vs MATLAB FFT has flipped conjugates?

I had to compute the DFT of a signal with 5 points with a hand-written method and using MATLAB's FFT just to see if they are equal. Taking the absolute value of both gives the same spectrum, however ...
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2answers
142 views

Down sampling an EEG signal

I have a set of 10 minute EEG signals that were sampled at 400 Hz and have 16 channels which corresponds to a 16x240000 matrix. These EEG signals belong to two different classes. I am trying to ...
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0answers
24 views

Decomposition of a non-stationary signal

Suppose $f(t)$ is a non-stationary signal which can be expressed as follow: $f(t) = A_1(t)\text{sin}(\omega_1t) + A_2\text{sin}(\omega_2t) + ... + A_n(t)\text{sin}(\omega_nt)$, where $0 \leq t \leq ...
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1answer
28 views

How to add a particular noise on a signal?

I have a simple ADC model (an input signal == sampled signal ). The adc should be modelled as with following values: 1.5 V (peak to peak).. meaning --> +1.5 V --> 0 dBFS ... how to do this ? The ...
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0answers
14 views

Basic in frequency-selective channel: part with decoding

Here I have asked about the basic of the theory of frequency selective channel and the user @Florian explained to me how to compute precoding in such case using the effective channel. I am just ...
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0answers
16 views

Convergence of LMS

I'm not really sure about the following question and don't know where exactly to look it up, so I'm asking here: I have an adaptive filter and compute the coefficients iteratively using e.g. LMS or a ...
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1answer
394 views

understanding discrete-time convolution in LTI systems

I'm trying to understand the discrete-time convolution for LTIs and its graphical representation. standard explanations (like: this one) start with the idea of decomposing an input signal $x[t]$ into ...
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2answers
215 views

Threshold for peak detection of noisy signal in frequency domain

I have a noisy signal (Gaussian Noise) with a known SNR and known Noise variance. This signal contains a number of Frequency components. My ultimate objective is to detect the components of the signal....
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2answers
147 views

doing sine regression to recover the paramters from a given signal

I have a discrete signal. I want to do sinusoidal regression to estimate the parameters such as amplitude, phase, frequency, etc. It is important to note I only have the signal values and have no ...
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1answer
28 views

Total Harmonic Distortion THD for the rectifier

I have a circuit with rectifier and this cause the non-linearity and consequently harmonic. I show it on the oscilloscope and then collect the signal from the oscilloscope to the computer by using the ...
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1answer
31 views

Non-coherent discriminator

I'm reading a paper about designing a non coherent discriminator for GNSS receiver. I came to the equation I'm not sure about that symbol < how would I write this in a small pseudocode ? for ...
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3answers
56 views

How to find the time of beginning of the slope of the signal?

I have a time signal in MATLAB format. Sampling rate is 100k, so it is roughly 5 seconds of signal. See the link below https://www.dropbox.com/sh/v7vev2j14i77mlk/AAA-X7JGMAzO6IyElYmFPFwra?dl=0 If ...
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1answer
53 views

machine learning on multiple signal at once

I am very new signal processing and I am asking this with the expectation that someone gives me a concrete guideline on how to approach my problem. The problem I need to solve is that I have 2 ...
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2answers
53 views

Can an audio recording tell whether it is made in a large or small room?

The conversation of one or more people will be analyzed. I think need to look for something similar to reverberation or echo in an audio signal. How can this be implemented? Update: small room is ...
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1answer
32 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) ...
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0answers
17 views

How to check significance of a channel? [closed]

I have a Brain signal which is multi channel. I want to check if which channels are significant for that specific task. How can I check this? Suppose, I have a multichannel EEG data-set of Alzheimer ...
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1answer
45 views

RF signal identification algorithms

There exist many, many analog and digital data transmission protocols. It is often difficult to tell which mode one listens to and tedious to do for many signals. In Ham Radio, a Reed-Solomon ...
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1answer
129 views

Prove that, in DFT ,interpolation in time domain is equal to replication in frequency domain

Given: $x[n]$ is an $N$-point sequence whose DFT is $X[k]$ $$x[n]\xrightarrow{\mathcal{DFT}} X[k]$$ then, Prove that: DFT of the same sequence after insertion of $(M-1)$ zeroes between successive ...
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0answers
36 views

Summing RMS Values

I'm trying to calculate the RMS of a signal whilst only having access to the current RMS values of the waveforms making it up. This is because I need to calculate the total RMS so I can use it to ...
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0answers
12 views

What is the difference between robust stability and robust performances for a MIMO system subject to uncertainty?

I am studying control systems and I am focusing on the case where uncertainty is present in the system. I have seen that in this case I have to be able to garantee robust stability and robust ...
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1answer
47 views

A Delay Between Two Filtered Chaotic Signals

it is a common practice to use a shift of cross-correlation peak to evaluate a group time delay of two signals (chaotic signals are included). Can one synchronously and equally filter these chaotic ...
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1answer
25 views

How to express time delayed discrete signals

Hi sorry this question might sound silly but, a signal $$x[n]=[ 6 \: 4\: 0\: 2]$$ what is $$x[n-2]$$ then?
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2answers
41 views

Meaning: channel unknown and known at the transmiiter

What does "channel unknown" and "known at the transmitter" mean? In books about signal processing, it has always mentioned it if capacity or transmission (estimation) is discussed. I can't understand ...
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2answers
253 views

why is my FFT magnitude of real time recording so volatile?

My goal is to do spectrum analysis of a gear motor. I used Python with the Pyaudio package and made a crude spectrum analyzer that displays the FFT as the sound is being recorded. I recorded 10 ...
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1answer
40 views

Is it possible to use a control scheme with a delay as prefilter?

I am studying control systems, and in my studies I have encountered the topic of control scheme of the form and I have seen thaht this control scheme is really useful since it is possible to add a ...
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0answers
8 views

How do I design a reference filtering control scheme with a lead compensator?

I am trrying to design a lead compensator for a system. I have the following control scheme: where $Cr(s)$ is a prefilter which can be a lag or a lead compensator. My obkìjective is to design $Cr(s)$....
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0answers
11 views

Why does the step response has higher overshoot if the zero is too slow in a lead compensator used as a prefilter?

Consider a control scheme of the following type: where $C_r(s)$ is used to filter the reference, and it can be a lead compensator of a lag compensator. One thng I don't understand is why if I ...
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7answers
11k views

Why Does the DFT Assume the Transformed Signal Is Periodic?

In many signal processing books, it is claimed that the DFT assumes the transformed signal to be periodic (and that this is the reason why spectral leakage for example may occur). Now, if you look at ...
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1answer
65 views

y(t) a of an integrator circuit

I have a signal $$ x(t)= \frac{1}{T} e^{-\frac{t}{T}} u(t) - \frac{1}{T} e^{\frac{t}{T}} u(-t) $$ and I know that it transits in a integrator circuit and I have to find y(t) in time and frequency ...
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1answer
42 views

Fit Rice Distribution for negative RSS

I measured the Received Signal Strength in dBm between a receiver $R_x$ and a transmitter $T_x$ at different distances $d_1, d_2, \dots, d_n$, and all the values that I obtained are (of course) ...
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0answers
39 views

Measurement inaccuracy

Does this measurement result comply with the specification or not? Why? The upper limit of a test is 50 m/s and your measurement result is 46.912 ± 10 m/s. The lower limit of a test is 5 mT and your ...
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2answers
24 views

Extracting different frequency bands (alpha, beta, gamma) from brain activity data

I am new to signal processing and despite googling about my question, I still couldn't find the solution. I have an Electrocorticography (ECoG) dataset. This consists of recording brain activity from ...
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1answer
90 views

What are some of the disadvantages of parametric PSD estimation methods?

Roughly speaking, the methods of power-spectra estimation can be divided in two categories : parametric and non-parametric. From what I understood, parametric methods assumes that the signal can be ...
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2answers
237 views

Regarding Bode plots; $H(s)$ and $H(j\omega)$

In circuit analysis, I understand the use of Laplace Transforms to obtain the impedance of a linear RLC circuit, ie transforming from the time domain to the frequency domain. In most texts I have seen ...
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17 views

Calibration the instruments

The Measurement systems and instruments are frequently calibrated. Do anyone know the reason behind different calibrations. I have read that the measurement uncertainty increases with every step in ...
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2answers
64 views

Inverse Fourier transform Of a triangular impulse

I have to find the expression of this graphic and after find the inverse Fourier transform of it. First of all I found that the expression of the graphic is $$ X(f) = \frac{1}{2} tri (\frac{f+f_0}{B}) ...

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