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Questions tagged [matlab]

MATLAB (MATrix LABoratory) is a numerical computing environment and a fourth-generation programming language. Use this tag with care.. see excerpt.

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How to detect the spreading code in MATLAB

Suppose we have the modulated signal $x = 10$ which is spread using one of the hadamard matrix codes (each column of matrix represents a code) as below: $$H = \begin{pmatrix} 1 & 1 & 1 & ...
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How do I play and record audio at the same time?

So this question is more related to Matlab itself. Some background info: I'm trying out the Exponential Sine Sweep method to obtain the Room Impulse Response with my laptop speakers and microphone ...
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1answer
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Error reading a .PCM file

I want to convert a .wav file with a sampling frequency of 44100 Hz to a 16 depth .pcm. I don't why I'm getting those peaks at the beginning of .pcm plot (second figure below 2). If you could ...
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Matlab spectral shift [closed]

I need a matlab codes to resolve this... This is using for a audio file. Download here. https://www.nasa.gov/specials/InSight-Sounds/06-MASTERRESAMPLED-48Kraw_velocity_0.6_normalisedx1.wav Matlab ...
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31 views

sum for a chirp signal

I have a chirp signal. In Matlab, the command is $s=chirp(t,f0,t1,f1)$. I make the following sum with Matlab: $y=rand(1,size(s,2))+s;$ Here is my question: What is the theoritical equation for $y$? I ...
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What is the difference between using corrcoef to compare two signals by column, and as whole matrices?

I have two matrices, which represent acceleration readings of the same event from two seperate sensors, and I would like to calculate the correlation coefficients so that I may get a measure of how ...
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1answer
41 views

Confusion about ensembles and averages in autocorrelation matrices

I just noticed that until now I often don't cared about the scaling of the autocorrelation Matrix in Matlab. I then checked with the book Statistical Digital Signal Processing from M. H. Hayes. There ...
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Why is my resampled signal cutoff when resampling with a windowed FIR filter in MATLAB?

I have an exercise to write a function which upsamples or downsamples a signal by a factor of F (integer) using a FIR filter windowed with a Kaiser window function. Exercise I had last week included ...
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31 views

Matlab: How to implement expectation of product of hermitian matrix

I want to implement the following equation in Matlab: $\mathbf {R}_\mathbf {z}^a(\tilde{f}) = \mathbb {E} \left[\mathbf {z}(\tilde{f}) \mathbf {z}^H(\tilde{f}+a) \right]$, $ \tilde{f} \in \left[0, ...
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19 views

Synthesizing a function from a fourier transform

So I have this question in a homework and cannot seem to solve it no matter what I try. Question: Use Matlab to find out what function in time x(t) resulted in the Fourier Series ...
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1answer
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how to lower frequency of a soubd file in matlab?

I am new to programming and sound processing, I have been using matlab to process sound files, a few of which are ultrasonic. my sampling rate is 250kHz. I Would like to be able to play the sounds at ...
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1answer
31 views

DFT of a series of RC exponentials

Context: I'm trying use matlab to apply a single-pole filter to a time-domain ramp waveform that is generated by a sequence of time-shifted "RC steps" that are added together. The time domain voltage ...
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1answer
26 views

Designing Rayleigh Fading Wireless Channel with particular properties [closed]

I have some information on particular wireless channel between an Access Point(AP) and K users as described in the picture below: How i can create this channel in Matlab?
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18 views

Wide-Band Lorentzian FDTD Algorithm

I want to convert a simulated gain/absorption of a material, which can be understood as a discreet (dispersive?) function $g_i(f_i)$ ($f$ is for frequency) or $g_i(\lambda_i)$, into $\tilde g(t)$ for ...
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11 views

Signal delay in phase interferometry?

I want to write program for phase interferometry to understand how its work. For the beginning I generate signal, which arrives on two antennas with delay. Matlab code: ...
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1answer
70 views

Why is this recursive DFT algorithm not equivalent to this iterative method?

Edit 1/30 - Taking @Fat32's edits into account, it seems like there is still an issue with the scale of the frequency axis. While version 2 correctly identifies the response at 1 HZ, version 1 seems ...
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1answer
45 views

Does dividing the magnitude spectrum of white noise by sqrt(2) give an RMS magnitude spectrum?

I understand that the RMS Amplitude of a sinusoidal signal is around 0.707 ($\frac1{\sqrt2}$) times the Peak Value, but this is not true for noise. However, an FFT of a noise signal indicates ...
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Applying a filter on an input sequence in matlab

Given a input sequence $x = {x_1, ... x_n}$ and a filter with l elements $h = [h_1, ..., h_l]$ with l < n. We want to filter the input sequence with the specified filter. My first thought was to ...
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1answer
34 views

Covariance matrix for sine wave extraction [closed]

we have added five sine waves with different phase and same frequency in matlab. we want to retrieve all the input sine wave back using covariance matrix method. kindly provide the solution for this.
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1answer
53 views

Why do DFT frequency buckets need to be divided by sample period?

edit: This is my first post in this community. I'm sure that my downvoter had a good reason to do so, but could someone please comment and tell me how I can better format my question? -- I have a ...
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Rotation invariant vs rotation variant

I have a very basic question. We have Rotation invariant filters and filters which are not invariant to rotation. Now let us suppose I want to apply one of these filters. How can I decide which one is ...
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1answer
44 views

Intersymbol Interference

Currently I have generated a ISDN 2B1Q signal and added a random signal to it,then I have designed a lowpass butterworth filter to remove the noise as much possible in MATLAB. My next task is to add ...
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Why is root square coherence seldom used?

Why most common programming languages used for signal processing (eg Matlab, python) don't have a "root square coherence" function, but only the magnitude squared one? I'm working on a MIMO problem ...
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Basics of Normalizing Cross-Correlation with a View to Comparing Signals

I'm trying to understand how cross-correlation is used determine the similarity of two signals. This tutorial offers a very clear explanation of the basics, but I still don't understand how to use ...
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1answer
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Berlekamp–Massey algorithm verification

I'm implementing Berlekamp–Massey algorithm for BCH codes, but I have some troubles with it: I don't realize how to verify this algorithm. Is there any methods to prove, that code works correctly or ...
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1answer
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What's wrong with this Whittaker-Shannon-Kotel’nikov interpolation implementation?

I tried to implement Whittaker-Shannon-Kotel’nikov interpolation formula but I get unexpected results: the reconstructed signal lags with respect to the original. I know that I can not expect a ...
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1answer
54 views

how can I design Chebyshev filter with 5th-order polynomial and 0.001%-allowed ripples?

I'm very beginner in signal processing. I need to design a Chebyshev filter with 5th-order polynomial and 0.001%-allowed ripples by using matlab as I found in a paper. I'm filtering pressure data ...
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1answer
48 views

Signal Denoising Uniformly in Frequency Domain

I have a noisy sparse signal containing number of frequency components. Is there any method to uniformly denoise this signal. in other words, a method that estimated and eliminates the noise power ...
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1answer
51 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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0answers
16 views

Error Probabilities over Generalized K Fading Channel

How do I integrate the average probability of error for generalized-k? How do I plot the results
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33 views

Bandstop FIR Filter in Matlab

I need to design a Bandstop FIR filter and find its impulse response & frequency response in Matlab. I was thinking that, for the impulse response, I should filter my FIR filter with a delta ...
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52 views

How to set sigmas and kernels for 3D-Laplacian of Gaussian filters to blob detection in Matlab?

I have written code according to a paper for Lung CT images, but its output wasn't correct. I think it is because of the setting of its parameters. The paper is about a multi-scale method using a ...
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2answers
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Need help cleaning noise

I have been recording sound sample from mouse vocalisations and noticed that a background noise appeared in the recording room. the noise is clearly visible in the spectrograms of the recordings as ...
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How to make function in time domain after fft fit with the corresponding function in frequency domain?

For example, I want to use fft to transform the simple function exp(-x.^2) defined in time domain. And the corresponding funciton in frequency domain is sqrt(pi).*exp(-k.^2/4). And I use the upper ...
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1answer
74 views

Sampling and reconstruction of signal in Matlab

I'm trying to write a program in Matlab that samples (using Nyquist theorem) and recovers signal. I got stucked on recovery part...recovery signal doesn't match with the original one (see photo). And ...
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1answer
25 views

integral filter

Assume we have a time domain signal: s(i), i=1:N. To apply a derivative filter to it, i.e. D*s, where ...
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31 views

The difference between the variance of white noise and narrow-band noise in Matlab

In Matlab, we can generate noise with zero-mean and unit variance by using "n = randn()". But in fact, the variance is not really equal to 1, but there is a slight error. Assume that the length of ...
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1answer
27 views

Finding delay parameters for watermarked signal

I have a watermarked signal WATERMARKED SIGNAL And the actual watermark WATERMARK In Matlab, I need to find out the delay parameters $d_i$ which can be considered as the embedded information.such ...
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1answer
31 views

Hough Transform not working to recognize a line

I have an image composed of small white dots that should stay on the same line. I wanted to recognize this line using the Hough Transform. To do that I binarized the image, calculated the centroid of ...
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1answer
29 views

How to use the iircomb filter in matlab

I have a sound file that needs filtering which looks like this: Hence I think that I have noise spaced equally at 832Hz. i tried to use the iircomb filter taken from mathworks website and i managed ...
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1answer
27 views

Root raised cosine parameter

I try to create matched filter for receive BPSK signal. Sampling rate of the signal is 228000 Hz, data rate 1187.5 symbols/sec, signal was shaped using root raised cosine filter with rolloff factor = ...
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3answers
69 views

How to filter my noisy square wave so that i can recover my signal using the Chebyshev Filter

I have a noisy square signal as input but it has a lot of noise. I should use a Bandpass filter to recover my signal. I know that the Chebyshev Filter is a bandpass filter; but it doesn't work. the ...
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27 views

About the power spectrum and confidence upper limit of a time-series data

For now, I have a coupled system with 5 variables and use the Runge-Kutta method to integrate. ...
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Need help with understanding the pros and cons of geometric and stochastic based channel models. Which one s preferred under which conditions?

https://www.adv-radio-sci.net/9/165/2011/ars-9-165-2011.pdf https://ieeexplore.ieee.org/document/7794648 https://pdfs.semanticscholar.org/c301/8463116117ea64f69638e15aa78fe9e84093.pdf https://www....
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1answer
16 views

Why do cutoff frequencies of a high-pass digital filter differ from the ones i used to transform it from a low-pass analog filter in MATLAB?

I need to transform an elliptic analog low-pass filter to a digital high-pass filter but i'm having a problem because the resulting filter has lower cutoff frequencies than the ones i set. Here is the ...
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1answer
27 views

Finding the fundamental frequency of a speech using autocorrelation function

I don't understand why do we use the autocorrelation function to find the fundamental frequency(F0) of a speech signal. I understand that: The autocorrelation function is used to show the similarities ...
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how to do supervised NMF source separation?

I know how NMF works by itself (unsupervised), but I am now interested in learning how it works in the supervised way. Suppose I have a clean isolated time domain signal of about 3 seconds in length ...
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1answer
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How to generate a biphasic pulse in MATLAB?

I am looking for an efficient way to generate biphasic pulse in MATLAB like the one in figure below. X-axis is time in seconds and amplitude is current from 0-20uA. P.S. The signal is an input ...
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system identification: MATLAB tfestimate gives different results for different Fs

So I have an experimental data; A is a chirp signal (sweep sine wave) and B is the response of the system. I identify the system as follows in MATLAB: ...
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30 views

How to do carrier aggregation?

I have generated 20 MHz bandwidth LTE waveform. I wanted to do carrier aggregation of this signal to get 100 MHz Signal. I want to understand how carrier aggregation is done mathematically, so using ...