Questions tagged [signal-processing]

Digital signal processing of sound, video or other single or multidimensional data

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Signal processing from Discrete data (Discrete Fourier Transform)

I am new one to Mathematica. So excuse me if my question is not absolutely accurate. I am trying to find all isolated frequencies in Fourier domain. And then to make inverse Fourier. And finally to ...
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6 votes
1 answer
316 views

Problem with Spectrogram

Some time ago I wrote a program to analyse a short segment of music and plot as a spectrogram in Mathematica. It allows one to find the notes in a weird chord for example. The example below is from ...
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1 vote
0 answers
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Phase unwrapping of transfer function model for calculating group delay [duplicate]

Suppose that I have a transfer function model ...
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3 votes
1 answer
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What do we get from OutputResponse[sys {u1,u2}]?

I understand what OutputResponse is doing in the first two examples below. ...
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4 votes
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What is this this application of KalmanEstimator doing?

I struggle to understand the Kalman filter and the documentation for KalmanEstimator. Please help me understand the first Application on that documentation page. The code in question is copied here: <...
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2 votes
2 answers
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Why does this PhaseRange not work?

Any idea why this PhaseRange does not work? BodePlot[-(1/(s + 1000)), PlotLayout -> "Phase", PhaseRange -> {0, 2 \[Pi]}]
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0 votes
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How to predict the delay of a higher order digital filter

My last question on this was a minimal example. I start with the following: freq=0.1; input=Table[Sin[freq t],{t,1,250}]; I use results above in two digital ...
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3 votes
2 answers
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How to predict the delay of a digital filter?

I define a simple digital filter. transferFunction = TransferFunctionModel[{{{0.13793103448275862*z}}, {{-0.9 + z}}}, z,SamplingPeriod -> 1] Then I put samples ...
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1 vote
1 answer
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How to excite a transfer function with continuous white noise

I'm trying to get the output response of linear system represented by transfer function, once the white noise is given as an input. Here's the code:- For generating continuous noise, I'm getting help ...
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Why can't I use my discrete lowpass filter?

I am trying demonstrate a discrete IIR lowpass filter using the feature of RecurrenceFilter described here. This is my filter. ...
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Chebyshev I LPF filter phase shift

I'm trying to design a Chebyshev filter with zero phase shift but I'm doing something wrong here and it would be great if anyone can point me the right way. My Functions are: ...
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3 votes
1 answer
116 views

How to conciliate results between Fourier and FourierTransform?

I can't match the analytical results of a continuous-time Fourier transformation with the results I get from a discrete Fourier transform using Fourier[] in ...
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0 answers
36 views

How to compute the unbiased fit variance considering the option "Weights" in "NonlinearModelFit"

I am doing a non linear model fit. I know how the fit variance is computed when I do NOT assign weights to the fit, for example: ...
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2 votes
1 answer
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Play two sounds at the same time in mathematica. For example the inventions of Bach NO.8

I use mathematica to play the Inventions No8 by Bach. I want to play the two parts (by right and left hands )at the same time. But I don't know how to do it. Can you help me? Thank you! ...
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2 votes
0 answers
90 views

Finding recurrence relation from an inexact numerical sequence

Consider the recurrence relationship d[0] = 0; d[i_] := (1 + Sqrt[1 + 4 d[i - 1]^2])/2 /; i >= 1 which generates the following sequence (generated by using <...
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12 votes
1 answer
634 views

Removing outliers from data

I am trying to remove outliers from the following data: ...
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1 vote
1 answer
158 views

Audio Digital Signal Processing

Resource and strategy request I want to identify resources and strategies to implement a Mathematica based solution for audio digital signal processing (DSP) and digital to analog conversion (DAC). ...
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1 vote
1 answer
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IIR Digital Filter: samples not matching the frequency response

So I am a small project in Mathematica involving a Chebyshev 4th order highpass filter, and to obtain its digital IIR filter with the bilinear transformation. Then I implement the differences equation ...
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0 votes
1 answer
100 views

Microfluctuations analysis and Power spectrum

I measured a parameter over time and obtained the values below: 0,627896 0,205004 0,259237 1,059125 0,832184 0,587992 0,565537 0,527323 0,460228 0,471958 0,26696 0,75367 ...
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1 vote
1 answer
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Why do I get this error message from LowpassFilter?

I have a list of numbers data of length 10^7. I have values rate = 100000.; cutoff = 2000.; I try to low pass filter with ...
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1 vote
3 answers
157 views

Find FT and r.m.s noise of a signal

I have a signal : ...
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0 votes
1 answer
93 views

Where to get the "SignalSystem" mathematica package?

I am reading this book: Filter Design for Signal Processing Using MATLAB and Mathematica.It can find on the following link: https://www.wolfram.com/books/profile.cgi?id=3841 It's mathmatica examples ...
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0 votes
1 answer
109 views

Building complex signals in Mathematica

How to build a particular signal in Mathematica such that we have a sine curve for half cycle, then have zeros for some time and this continues? It is simple to have the zeros for the second half ...
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1 vote
0 answers
59 views

How to compute Total Harmonic Distortion (THD) for the following signal?

The signal is as follows Sin[x - j] with $j$ being ...
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4 votes
2 answers
217 views

Sampling and filtering data

I'm trying to teach myself about sampling and filtering — and I'm not sure if I'm misunderstanding the concepts or misapplying Wolfram Language. I started by creating a simple test signal with ...
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3 votes
1 answer
71 views

How to code a Sum Block when working with Transfer Functions?

I am working using transfer functions models with Mathematica and i am missing a basic feature like the ability to use a Sum Block. How could the model above be modeled? Considering: ...
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5 votes
1 answer
265 views

Why doesn't HighpassFilter fully remove the DC component? [duplicate]

The high pass filter is not completely removing the DC component. See the picture. Blue is the signal before filtering, green is after. Here is some background on the subject matter. I'm studying ...
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5 votes
0 answers
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How to train each layer in a Neural Network so they optimize different loss functions in an adversarial network?

Example NetGraph to illustrate the idea (Input is an online signal with a value between -1 and 1, Noise is Gaussian Centered at 0 and standard deviation 0.1, EvilNet is constrained to output a value ...
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2 votes
0 answers
83 views

Sound steganography with `InverseSpectrogram`

Here is my code of how to hide a message inside a sound: ...
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0 votes
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44 views

How can I deconvolve a spectrum to get the information about each of the deconvolved spectra?

I have a spectrum with two peaks. I want to deconvolve it by gaussian so that I get the parametres (e.g. peak position, area, FWHM, Height) of each deconvolved spectrum. I have tried the following: <...
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22 votes
2 answers
974 views

Can we use Mathematica to design an electronic active filter?

How can we use Mathematica to design an electronic implementation of an active filter?
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1 vote
0 answers
90 views

How to convolve two audio signal?

Can we obtain reverb effect by convolve two audio signal? Here are some example. https://www.bilibili.com/video/BV1vE411h7W2
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0 votes
1 answer
161 views

Are there some programs about inverse Fourier and Laplace transfroms?

To be more exact, I have a function F[w_,s_], where $w$ is the Fourier transform of $x$ and $s$ is the Laplace transform of $t$. Now I want to perform the double inverse transforms $s\to t$ and $w\to ...
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1 vote
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57 views

SpectrogramArray timescale

I have a 600 second @ 8000 Hz WAV file which need to be analyzed in detail in terms of events (red parts in plot) defined in time and frequency that need to be rather exact, in particular the ...
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Is there some programs about the fast inverse descrete time Fourier transform

At first, I give the definition of the inverse discrete-time Fourier transform $$\phi(s)=\frac{1}{2\pi}\int_{-\pi}^{\pi}\exp(iks)f(k)dk$$ Here what I use is ...
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  • 153
1 vote
1 answer
302 views

DSP filter problem in the simulation of a Lock-In amplifier

I wanted To explain to students how a Lock-In amplifier works. The best way is to simulate the behaviour of one. However, in my program, I get unexpected behaviour, which I suspect has to do with ...
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1 vote
1 answer
112 views

Noise filtering in audio

I was given audio with white Gaussian noise and i have to implement two types of filter: Rectangle and Triangle that filter out redundant frequencies and reduce the amount of noise Here is the code ...
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0 votes
1 answer
124 views

obtain the phase between two signals [duplicate]

I would like to calculate the phase between two signals like f= Table[Sin[x-0.8],{x,-100,100,0.1}] g= Table[Sin[x],{x,-100,100,0.1}] For doing that I use the <...
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2 votes
1 answer
201 views

Amplitude and Phase of a Periodic Signal (Fourier Series) [closed]

Please consider the following periodic signal (by "w" I mean Omega naught): f(t)= Cos(wt)+3sin(2wt)+5cos(6wt) How to plot its amplitude and phase spectrum exactly like the format and pattern ...
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3 votes
1 answer
928 views

how to plot the amplitude and phase spectrum of a Fourier Transform in this specific pattern?

I'd like to plot the Amplitude, and phase angle spectrum of the FourierTransform[Exp[-a t] UnitStep[t], t, ω, FourierParameters -> {1, -1}] (The Fourier ...
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4 votes
1 answer
112 views

Finding group delay of transfer function

I'm having trouble finding the group delay of a transfer function. I've seen a solved question on here about finding the group delay, but I want to understand why my method doesn't work. Here is some ...
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2 votes
0 answers
61 views

How can i use Butterworth filter written in matlab to Mathematica

i need help to convert this code written in matlab about Butterworth filter: ...
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2 votes
0 answers
119 views

How to reform a expression to improve numerical stability?

In engineering, we usually have to solve a function numerically, which has no symbolic computation ability and may using a low percision data type like fp32 or even ...
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9 votes
1 answer
209 views

How to reproduce Spectrogram from SpectrogramArray?

I'm trying to reproduce the result of Spectrogram from SpectrogramArray, but having no luck, any help? What I've got so far: <...
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1 vote
0 answers
27 views

What's the parameters of the Spectrogram function

The Spectrogram functions only has these parameters listed: Spectrogram[list,n,d,wfun] What's the value of the other ...
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4 votes
1 answer
95 views

White noise at non integer intervals, bug or my mistake?

I'm intending to add white noise to a simple periodic signal ...
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1 vote
1 answer
105 views

Fourier Spectral Analysis [closed]

I'm currently working on an engineering exercise that goes as such: I know that I need a step function to model the square waves, but I'm having trouble finding the right functions to generate the ...
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1 vote
1 answer
112 views

Track the location of of dot from noisy image

https://imgur.com/a/SnTYESG (subtraction between the image) https://imgur.com/a/ZdOS5wf (orignal image) From the original image, since my CCD camera is bad, I cannot really see anything. However, ...
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1 vote
1 answer
155 views

Finding the phase difference between fundamental harmonics of two waveforms [closed]

I have two periodic non-sinusoidal waveforms $WV1$ and $WV2$ (See Figure). I want to extract the fundamental components of these two (i.e. $WV1_{F0}$ and $WV2_{F0}$) and find the peak amplitudes and ...
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  • 169
1 vote
1 answer
98 views

Remove regular transient spikes from - otherwise - pretty level data

and let me just say thank you for all the help you good people have been providing to stalkers like me through the years. So, in the next few days or months or years, I'll be acquiring data of the ...
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