Questions tagged [signal-analysis]

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Computing the Power Spectrum Density (PSD) on a CSV File in Python

im quit new with signal processing and im trying to calculate the PSD of a signal im sampling. the signal is an output of a DC buck converter this is the code im using and this is the plot im getting ...
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3answers
41 views

Is there any algorithm to decompose a wave into a set of given frequencies?

I heard about Fast Fourier Transform can decompose any waves. But it seems like it was hitting for "all frequencies", namely, n HAVE TO be from 0 to N-1! What if I want to decompose the wave into ...
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1answer
340 views

Recover IQ samples from signal

I have a data acquisition device that provides me with an array of integers that represents a modulated signal (let's say QAM16). I would like to recover the I and Q samples from the raw time-domain ...
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1answer
16 views

Autocorrelation Computation with MATLAB

I have done the computation of the autocorrelation of a sequence (vector), here called "frame", and I have plotted it. Here the code: The resulting graph is: I do not understand the position of the ...
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1answer
93 views

Figuring magnitude and phase response

I've got a linear time-invariant system $$y[n]=\frac{8}{9}y[n-1]+x[n]$$ which I transformed into a transfer function $$Y(z)=\frac{8}{9}Y(z)*z^{-1}+X(z) =>\frac{Y(z)}{X(z)}=\frac{1}{1-\frac{8}{9}*z^{...
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1answer
20 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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1answer
45 views

How to determine sampling frequency for an x(t) signal avoiding aliasing?

The antitransform of the function is given: $ \hat{x}(f) = \frac{123 + i246\pi f}{246 - 24600 \pi^2 f^2 + i4920\pi f} $ I'm asked to determine which frequency can I sample using the function x(t) ...
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1answer
628 views

Frequency spectrum of complex equivalent Baseband Signal - Frequency Content around carrier frequency

Basically my objective is to generate a complex equivalent baseband signal of an AM modulated wave in MATLAB. Then to view the difference in frequency spectrum of AM modulated RF signal vs complex ...
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0answers
16 views

Minimum statistics noise estimate - how to calculate the underestimation factor?

I have implemented a basic noise estimator using the minimum statistics method. Noise power estimate is obtained as a minimum of the short time power estimate within a window of subband power samples. ...
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1answer
110 views

application of wavelet to vibration signal

I ask you to help me to interpret this figure corresponding to a diagnosis of gear failure using CWT (Haar); I have already worked on the analysis of the vibratory signals using the FFT; But since the ...
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2answers
239 views

how fast can you sweep sinewave

I am asking specifically about discrete sound signal, non dithered 16 bit 48000 Hz pcm/wav format. My question is, how fast can you change sinewave frequency before it distort? Imagine a frequency ...
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0answers
29 views

How can I convert a vector into image? [closed]

Suppose I have a signal of random values. For Instance, I have a random number vector x[n] where, x_n = rand(1,100); %matlab syntax; I want to generate Image ...
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1answer
124 views

Distinguish between sinusoidal oscillations and rythmic pulses

I want to distinguish between a sinusoidal oscillations and rythmic pulses. Which method can i use to do that? I want to implement a detector that can distinguish between this two types of signals. ...
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1answer
76 views

GPS Code Phase usage

During Cross-correlation process: xcorr=ifft(fft(a)fft(b)∗) we have frequency offset and code phase offset. How is it used later in the process of finding a ...
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1answer
168 views

Overlapping power-of-cosine windows with constant weight

I would like to refer you to a relevant question I posed on the Math StackExchange: A generalisation of the Pythagorean trigonometric identity. As can be seen from the question and the answer, what ...
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1answer
48 views

Measure 3-D length using smart-phone's accelerometer

I'm wondering if we can measure 3-D length only by our smart-phone's accelerometer. And we all know these low cost IMUs are not accurate. You can model accelerometer's error this way: $$ a = f*a' + g ...
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1answer
429 views

MFCC Classification

I'm working on gender estimation from speech signal and I completed MFCC feature extraction. So now I'm trying to estimate gender from these features. But I have frames for an audio file and I ...
2
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1answer
38 views

Transfer function given as z-Domain fraction: gain calculation

I am stuck on a question regarding transfer functions. I have the answer and have attempted the question but am having trouble solving it. Q: Given the transfer function of a digital filter is (5z-5)/...
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0answers
17 views

analyzing experimental seismic signal Vs real time seismic signal in graph [closed]

I am trying to analyze this graph on this link .On this link the they told us about real time seismic signal are more complex then experimental seismic signal but " it shares many physical ...
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1answer
214 views

Phase Modulation and Intermodulation Anomaly ? (Spectrum plots inside - **Updated**)

I have a MATLAB script for modelling a two tone signal (a sum of two sinusoids) going through a non linear transfer function (such as an amplifier). The amplitude of a signal is amplified non linearly,...
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1answer
260 views

Is convolution distributive over multiplication?

Is there any formula or expansion for $$a(t)*[b(t) \cdot c(t)]$$ $$a(t) \cdot[b(t)*c(t)]$$ where $*$ denotes the convolution? By expansion I mean something like $a(t)\cdot[b(t)+c(t)]=a(t)b(t)+a(t)...
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1answer
80 views

Audio from multiple microphones mixed to mono and ASR

I am trying to do speech recognition on an audio file which has 1 channel (mono). My problem is that the channel is comprised of the signal of 3 microphones which have captured the audio at different ...
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1answer
24 views

Removing vocal but retaining all background ambient noises

I have one audio file containing human speeches, a lot of ambient noises like audience laughter, birds chirping, sounds of natures etc.. Now I want to separate it into two audio files where one ...
2
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1answer
308 views

How to make sense of audio file's $\textrm{dBFS}$?

I'm trying to build a song visualizer using the FFT method. When I analyze the audio, I get the $\textrm{dBFS}$ value for each frequency range. From my understanding, $\textrm{dBFS}$ is in the range ...
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2answers
58 views

Augmentation for EEG signal classification using Deep Learning

Augmentation is a technique that we use in deep learning for expanding the training dataset. It includes different ways of modifying an image and adding it to the training dataset. My question is if ...
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2answers
56 views

how can we align wto signals with a time lag in between?

I have two signals from two different sensors. I cropped the area i am interested in from both sensor signals. The problem is that the signals start at different time instants. I am searching for a ...
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1answer
54 views

How to apply baseline methods to MNE preprocessed raw EEG signals?

I am new at EEG preprocessing and classification. I have followed Clemens Brunner's blog https://cbrnr.github.io/2018/01/29/removing-eog-ica/ as a tutorial for MNE. This is how I have preprocessed ...
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0answers
12 views

Phase concentration for a broad range of frequency over time

I have local-field potential signals from two animals and I am trying to do phase analysis on these signals. What I am interested in is how phase concentration (or interatrial phase coherence) changes ...
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2answers
34 views

Length of DFT defines whether I see the harmonic or the dominant frequency

I have a number of signals that are periodic. I use an fft transformation to obtain the dominant frequency of each signal. In order to increase the frequency resolution I zero pad the signal before ...
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0answers
40 views

pressure decay filtering

So, I've been dealing with a series of pressure decay curves from a pressure transducer. Each one has a waterhammer effect as a consequence of shutting down pumps. Here are examples of 3 curves: I'm ...
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1answer
51 views

Algorithm for detecting whether a signal stored in rolling buffer is Increasing, Decreasing or staying Constant

I have a data signal which is generated at constant time interval. It is a real world measurement and thus exhibits some noise in its value (it fluctuates approx + or - 20 units). The noise is fairly ...
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0answers
24 views
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1answer
99 views

How to detect the maximum resolvable spatial frequency of camera?

I am trying to calculate the minimum line pixel width that can be distinguished from noise as shown in the camera test chart in Figure 1 where the thinner lines on the left are getting more and more ...
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1answer
32 views

How to measure algorithmically side lobes in real data

I want to measure algorithmically the following parameters in a given FFT data (real numbers). peak side lobe levels side lobe levels 
side lobes nulls The following image illustrates parameters I ...
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1answer
22 views

I have the following accelerometer signal, I want to segment or slice the signal into Red parts and Green parts

I want to count steps which are basically represented by peaks in the signal. the red part in the signal doesnt correspond to any walking activity, I want to ignore them. Any help on segmenting or ...
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0answers
26 views

I want to invert my fourier transform components to waves again

Hi I am using R to analyze some data I basically did fft(data) and got a vector of complex numbers but from that now I want to remove certain harmonics from my actual wave but how do I convert one of ...
2
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1answer
57 views

How to obtain an envelope of my mas-spring damping curve?

I have my program for mass spring system made with Euler method...and I can't menage to obtain envelope of the BLUE damping curve. Can you help me? ...
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0answers
5 views

control points and concentration of sampled points in a parametric curve

Can anybody explain to me what the following sentence means? "In cubic Hermite, as any parametric curve, the control points density reflect in the concentration of sampled points in more dense parts ...
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2answers
2k views

Performing a Deconvolution

So I have the following data: ...
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2answers
25 views

Using the traditional instruments for measuring high frequency signal

All we know that we can not use the probe for measuring the high-frequency signal (microwave signals). I still can not understand the reason. I have read that the reason because of the wavelength size ...
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1answer
33 views

How to make signal smooth using filter?

I have measured the output of a mechanical system and obtained the signal shown at the attached image. I want to make it smoother by removing the chattering (I think it is called chattering). In order ...
2
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1answer
31 views

Sample & Hold: Estimate jitter delay of an ADC

I've got a question regarding the effects of sample and hold. My input signal is $x$, and my output signal $x_{SH}$. The error between the signals is $e_{SH} = x_{SH}-x$. The sampling frequency is ...
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1answer
34 views

Similarity or Relation between Walsh Hadamard Transform and Slant Transform

Is there any relation between Walsh Hadamard Transform and Slant Transform? Or is there any common property or similarity?
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1answer
63 views

About the variance of the coefficient of narrowband noise when using signal-space representation

Assume that n(t) is a white Gaussian noise process with zero-mean and power spectrum density $N_0/2$. By using the signal-space representation, it can be expressed as: $$n(t) =\sum_{j=1}^N n_j \...
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0answers
39 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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2answers
77 views

As of 2019, which discrete nonlinear, time-invariant systems with memory are considered “easy” to model and identify?

There are several types of discrete nonlinear time-invariant systems with memory ("NTIM") which are considered "easy" to model and identify. Any such system can be represented using a Volterra series, ...
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1answer
66 views

One Too Many Non-Zero Eigenvalues in MUSIC DF Algorithm

I'm working on simulating the MUSIC algorithm in MATLAB to determine the azimuth angle of arrival of a simulated signal. My virtual antenna array consists of 4 antennas arranged in a plane. While I ...
2
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1answer
81 views

Impulse response of a transfer function

Lets say we have a transfer function from an LTI-system that goes as follows, and we want the impulse response for it: $$\frac{10\cdot e^{\left(-\mathrm{i}\right)\cdot \pi\cdot f\cdot 8}}{5+\mathrm{i}\...
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2answers
142 views

Wavelet Filter Coefficients from Scaling Filter Coefficients

I am trying to develop a new type of wavelets and I found out a function that following a particular two scale relation. The function at a scale $t$ say $x(t)$ can be related in a finer scale $x(2t)$ ...
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2answers
53 views

Estimate “speed” of repeating signal pattern

I have a digitized signal containing a repeating pattern. One could call it periodic, but the time for one period is not constant. The "speed" with which the period is advanced can change over time. ...