# Questions tagged [signal-processing]

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

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18 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: ...
53 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 ...
22 views

### Calculate Energy of signal by coefficients of continuous wavelet transform

I have applied ContinuousWaveletTransform to my data. And now I want to calculate the Energy of signal in accordance with Parseval theorem To find Energy I would like to use quadrature formula: . I ...
139 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: <...
19 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 ...
68 views

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

I'm intending to add white noise to a simple periodic signal ...
73 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 ...
80 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, ...
111 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 ...
28 views

### How to get the 1D radially averaged spectrum from grid

I have a grid with spacing of 1 m in $x$ axe and $y$ exe, given by: ...
62 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 ...
42 views

### How can I generate a Poisson gap sampled list?

tstart = 0; tend = 3; num = 1024; tstep = (tend - tstart)/(num - 1); list = Table[i, {i, tstart, tend, tstep}] // N; Histogram[list] I have a list of 1024 points ...
32 views

### Find repeating chunks in audio file

I have a long audio file (12+ hours). I know that there are some unknown small (2 minutes each or thereabout, it varies) repeating (not bit by bit: it is recorded with a mic) chunks in it, repeating ...
22 views

### Plotting DiracDelta series

I'm dealing with the Fourier Transform of the following signal: ...
23 views

### Why is the number of sample points of an audio changed after being export?

I have an audio audio001 and I need to export/import it so that I can do auto-correlation. Below I used ...
50 views

### Plot Audio DAta

I am a beginner in mathematica. Currently i am working on audio file my problem is when i extract audio information using BinaryReadList and try to plot it works with mono wav file but cannot get ...
40 views

### How to filter audio to get best results in correlation?

I am trying to recognise the alphabetical letters by saving some data of records of me and others saying each letter, then comparing a test audio not contained in the data to each letter using the ...
62 views

### Fourier Transform and Inverse Fourier Transform of Lists

I am trying to compute the Fourier transform of a list, say an array of the form {{t1, y[t1]},.....{tn, y[tn]}}; apply some filters in the spectral components, and then back transform in time domain. ...
57 views

### Removing Extra Points When Finding an Audio Envelope

I am trying to reproduce Camtasia's way of displaying audio signals which is a strictly positive envelope of the audio signal and very easy for me to identify some sounds visually. These are displays ...
164 views

### Implementing an anti-alliasing filter in Mathematica

I'm experimenting with FFT simulations. I'm generating transient data at the some sampling rate, down-sampling this (mimicking a device's behavior) to 2048 points. Then take the FFT using ...
375 views

### How can I generate a sin wave with power law noise?

I am interested in simulating a signal with different types of power law noise, as entitled in wikipedia, "Color of Noise". (The audio examples are pretty cool). Basically, white noise, which many ...
51 views

### How to compute delta coefficients in mathematica

I want to get delta coefficients calculated. The definition can be found here. However, I don't know what to do with the minus indices. I have tried computing it in a slightly different way, namely: <...
64 views

### GaussianMatrix algorithm details

GaussianMatrix[] supports a Method -> "Bessel" option which the documentation describes (in the Details section) as: With ...
256 views

### Adding white noise to a signal of two variables

When a signal depends on two variables, e.g., f[k1_, k2_] := Exp[I 0.75 (k1 + 0.3 k2)] + 1.5 Exp[I (0.2 k1 + 0.3 k2)] + Exp[I (0.2 k1 + 0.4 k2)]; where ...
132 views

### Signal Processing [closed]

The image above is the list plot of discrete data I'm working on. Please I need help on how to zero out all the high amplitudes signal from the data. That is all the data in areas circled, I want to ...
71 views

### Sound Processing frequency Dynamicly

Would like to know if there is a method to call upon the frequency of a song at a given time for instance at 0:34 second the frequency is x ; But to do this live meaning as long as the song is ...
135 views

### Approximating decay rate of an amplitude and frequency of an oscillating function

I have an InterpolatingFunction constructed from a discrete set of values obtained by numerical methods. Let's denote it $f(x)$. The function demonstrates an ...
154 views

### How to find the rectangle with those text

In this image: I want to find this rectangle with all contents(without those grid's lines) I think the total of the pixels can help a little like: ...
496 views

### Deleting noisy data from a plot (manually) and export the best remaining data

I have the following temperature time-series. As you can see it contains very very noisy points in some periods (Fig.A). I tried to approach the best data(the black one in the center) based on the ...
139 views

### How to get exact frequencies in the time response using InverseFourier?

I have amplitude data varying with frequency for a signal. From that I want to generate time response in such a way so that if I take Fourier I can get the ...
259 views

### Deconvolution using Fourier transforms

I have a 2D signal in the form of a function $g(x_m,y_m)$ given as  \begin{aligned} g(x_m,y_m) = \ & \int^{\infty}_{-\infty} \mathrm{d}x_o \ \mathrm{d}y_o \ \frac{1}{\varepsilon^2} P(x_o - x_m,...
496 views

### Generate noise time series with given data's PSD

I have PSD data as a 1D array, function of frequency(rad/sec). It is like powerspectrum for damped oscillator. Considering 3 modes, PSD is shown here. I want to generate noise time series which ...
74 views

### Processing and visualizing data to show Doppler shift [closed]

I want to write a program which can read a .wav file and manipulate the data so I can observe the Doppler effect in a plot. My problem is I can't figure out a way to isolate the frequency x time. ...
43 views

### How to force the output to be in terms of a specific function?

I have a rectangular function rect[t], which is a window function with values of $1$ in the interval $(-\frac{1}{2},\frac{1}{2})$:- ...
66 views

### Butterworth single pole, 5 Hz cut-off frequency on accelerometer data for single axis

I have read other posts here on using the Butterworth filter in Mathematica, however, I am having a hard time understanding the chain of functions and their parameters as applied to my case, and I am ...
738 views

### Processing images from NASA's Juno Jupiter Orbiter

Question Can you help me improve what I’ve done to create an enhanced-color picture from an image provided by NASA’s JunoCam? [My work is shown in the penultimate image of Jupiter in this post.] I’...
348 views

### Frequency of ticks in mechanical watches

I'm looking to find the frequency of a relatively large dataset (or a relatively short audio file) of a repeating sound, like so: Here are the original files, for those willing to play. :) eta2412 ...
284 views

### Fourier transform of a complicated function

This question is related to "Numerical Fourier transform of a complicated function" from 2012. I have pretty much the same problem: I have a function $f(x)$ which is complicated to evaluate, and want ...
49 views

### Create tone with adjustable frequency/amplitude

How can I play a tone and adjust its frequency and amplitude? As an example, say I wanted to play a SquareWave with a slider for frequency and amplitude. Using a <...
269 views

### Sample rate severely influences quality of ButterworthFilterModel?

I've hesitated for a while about whether this should be posted to dsp.SE or not, but still decide to discuss it here. Today I was playing with ...
114 views

### Butterworthfilter highpass/bandpass

this should be a fairly straightforward question since Mathematica has included functionality to filter data. Nevertheless, I am not being successful to solve the problem. Following the proposed ...
81 views

### Missing data - reconstructing large gaps with an autoregressive model

I am looking for a similar function as fillgaps in Matlab which helps to "replace missing samples in an otherwise uniformly sampled signal by fitting an autoregressive model to the samples surrounding ...
186 views

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### Filtering data with timestamps

How to apply filter to data that was sampled in certain moments of time? Examples from documentation deal only with uniformly sampled data: ...
32 views

### Error using ListCorrelate for Overhang parameters nonzero machine-sized integers

I've encountered a problem using the ListCorrelate function which I haven't been able to solve or find much information on. Using the following code: ...
59 views

### How to get a single evaluation of RandomReal in a Block

I want to generate (and eventually sample) a sine wave with a random frequency in the range [½, 1] (i.e. capture somewhere between half and one period of the waveform over the domain [0,1]). The two ...
116 views

### Fourier Scaling Issue

First a little background: I’ve looked at the following discussions on StackExchange and still racking my head on Fourier What are the most common pitfalls awaiting new users? Discrepancy between ...
159 views

### remove noise while preserving peak

I have a data (see this link) which has some wiggles at both end. I tried to apply different filters to smooth the data, like this ...