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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Using matlab to simulate SER VS SNR of 4QAM [closed]

I'm trying to use Matlab to simulate SER VS SNR of 4QAM. For example, transmitting a 1+j symbol but received -1-j, but I couldn't get the plot.
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Nyquist closed loop [closed]

So i have my system: $S = (0.4182/(s^3+1.539s^2+3.935s+3.628))$ And i need to use this line of code in matlab and find the system $>C = tf(K, [T,1]);$ ( $C = K/(TS+1)$ where the hodograph S*C ...
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I can't implement plateau limit histogram equalization algorithm using MATLAB

i tried to implement this research paper using MATLAB. Unfortunately, my result is not same with the original result. Here is my try step by step: ...
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25 views

up chirp and down chirp

The expression for a HFM up-chirp is $$x_1(t)=e^{-j2\pi K\log(1-\frac{t}{t_0})}$$ with $\frac{-T}{2} \leq t \leq \frac{-T}{2}$ and $K=\frac{Tf_lf_h}{2(f_h-f_l)}$, $t_0=\frac{T(f_h+f_l)}{2(f_h-f_l)}$....
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How to plot the periodic digital spectrum?

In a previous answer, Dan Boschen wrote (emphasis mine): First let me explain the "unfolded" digital spectrum: If you allow the frequency axis of the sampled signal to extend to $\pm \infty$, ...
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How to solve Gaussian Elimination for decoding Fountain code? [closed]

I have converted my 441x63 binary matrix into decimal and trying to do Gaussian Elimination. (Conversion is done to reduce computational power) Now, for example, I have the matrix in the decimal ...
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1answer
22 views

Parallel form filter design

I have a transfer function coefficients as following: [b,a] = ellip(4,.2,40,[.41 .47]); I'd like to factor this system into its PFE using ...
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23 views

Problem in finding the delay between two signlas

I'm using find delay block to estimate the delay between two signals. Here is my configuration parameters : The error that i'm facing :
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28 views

Matlab normxcorr for 1D signals

I am very surprised not to find a version of normxcorr2 for 1D signals in Matlab ! I implemented something like that by hand (with 2 for loops, and normalizing the template as well as the window under ...
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Simulink cross correlation issue

here is the Simulink model that i'm using : The matlab function script : function tau = fcn(sig,refsig) tau = gccphat(sig,refsig); The errors :
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Implementing cross-correlation with argmax in Simulink

How can I implement this in a Simulink block? I want to create a block that has two inputs (two signals, one of them is delayed) where the output is the value of the delay that gives me the maximum ...
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52 views

Difference between Fourier-Transform and FFT of rectangular pulse

I'm trying to find a link between the Fourier-Transformation of aperiodic Signals and the FFT of them. So to start with a basic example, let's take a rectangular pulse with width 0.1s and amplitude of ...
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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
50 views

Large spike at beginning of signal after applying Bandpass filter

Foreword: I am a PhD student and fairly unexperienced with many signal processing and engineering concepts, please be gentle. I am attempting to filter out a frequency range of 1Hz to 2Hz from a 2....
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Understanding and converting Matlab's coarse frequency compensation function

I am trying to understand and convert to C Matlab's coarse frequency compensator the documentation for which can be found here: Documentation Matlab's design itself is based on this IEEE paper: ...
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35 views

Bandwidth in the filter-Hilbert method

I understand that the Hilbert transform on broadband data produces uninterpretable results. And so we first bandpass the data, and then run the Hilbert transform. My question is, how wide can the ...
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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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How to convert from .wav (hydrophone data) to pressure (SPL)?

I am new here, since I started recently with signal processing. I am trying to analyze a .wav file recorded by a hydrophone, however, I need to convert it to SPL. I have a calibration file which ...
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PSD graph of GPS L1 Signal on MATLAB

I'm trying to analyze GPS L1 C/A signal on MATLAB. I could generate the PRN codes(binary signals). After I add NAV Data to the PRN code using modulo 2, I need to modulate it using BPSK. I also could ...
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1answer
49 views

Understanding Matlab's Automatic Gain Control function

I am trying to understand the automatic gain control block provided by the communications toolbox. The documentation is here: Documentation My questions are in regards to two of the configurable ...
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I am trying to plot ads-b signal and decode it using matlab

I am trying to plot ads-b signal and decode it. I have a wav file having ads-b signal and I can get first picture using next code. ...
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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 ...
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33 views

Matlab Plotting custom constellation along with decision regions

How do I create a custom constellation along with decision regions in Matlab, any help is greatly appreciated
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4answers
62 views

concatenating short noise sequences

I'm trying to merge 2 identical audio files. The Audio file is nothing more than white noise generated using MATLAB commands ...
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How to understand the sound parameters so that it can be reproduced in Matlab

I am reading a paper called "Mouse Auditory Brainstem Response Testing". In order to make the experiment myself I would like to create the stimulus sound using matlab. When describing the sound (in ...
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1answer
57 views

What is the time reversal convolution

Given a signal $r(t)$ which is a result of convolution between signal $x(t)$ and a channel $h(t)$ as below : $r(t) = h(t)*x(t); $ what I know, the time reversal convolution can be process as ...
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32 views

How to filter power line noise from ECG?

currently i'am trying to get rid off power line noise (50/60 Hz) from an ecg. Specification: Bandwidth of the ecg 0.05 - 150 (achieving this with a butterworth second order bandpass) sampling rate ...
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Signal similarity analysis after cross correlation

I have a time series signal and using this as reference, from the main data set extracted possible matching sections using cross correlation technique.(xcorr matlab).Based on with the threshold xcorr ...
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1answer
33 views

How can i define the vector to variable scalar?

I have A,B,C,D,E values all in size 1x1155. A=[1.0001, 1.0005, 1.00010,...,1.0009]. similar to B, C, D and E. I need (A(1)+B(1))/(C(1)+D(1)E(1)) + (A(2)+B(2))/(C(2)+D(2)E(2)) + ... + (A(1155)+B(1155))...
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1answer
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Designing a 2d low pas filter in fourier domain for an image

Firstly this is not a homework question. I am working on a project and my professor gave me this task so I can also learn about filters and fourier domain. I have a picture that is 2800 x 4500 pixels....
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1answer
39 views

Cross correlation to compute delay between two lines does not work

I have zero experience with signal processing, and I am stuck in what I believe to be a very simple problem. I am trying to use the xcorr in matlab to find delay between two signals. The signals are ...
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1answer
45 views

Real Fast Fourier Transformation (FFT) in 2D changes with changing the axes order

I am using Python to calculate the real FFT for a 2D array. I found that the real FFT function does not return an array with the same size as the input array, rather, it returns an array with the same ...
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How to applying window function to get same result with pwelch in MATLAB

I'm trying to calculate the power spectral density (PSD) to analyze signal power. To do so, I wrote a MATLAB code with the great help of others and below is my code. ...
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1answer
59 views

How to filter a white noise or random noise in Matlab Simulink?

I am working on a sun-synchronous satellite Simulink model wich determines its attitude from a Sun sensor and a star sensor whom measure the sun and star direction in the satellite body reference ...
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1answer
31 views

Pole Zero plot given a Transfer function

I've been looking at how to plot zeros/poles based on a transfer function. I found a couple of Tutorials online. In the first youtube tutorial, the author brilliantly explains how to plot the zeros/...
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28 views

2-D low pass filter

I have an ultrasound signal that is 1536x128. I first downsample the signal by a factor of 2x2 in x and t, then I upsample the missing data with zeros, then I do an fft, fftshift, then another fft to ...
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42 views

Scaling of the PWELCH function in MATLAB

I am trying to compute the power spectral density of a random signal using the PWELCH function in MATLAB. Since I think have not understood properly how Pwelch scales the PSD, I wrote a sample ...
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25 views

Require explanation for Matlab freqz2

Question I browsed the code of the Matlab freqz2 function (to find out how it is different to simple fft2.) First of all it ...
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3answers
42 views

FFT error when number of samples growth - Matlab/octave

I see when I increase number of samples, the imaginary error part of the FFT growth due to the error of sin(n*pi)!=0 where n is the index of the sample in Matlab or octave. Is there anyway to force ...
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55 views

What's wrong with my M-ary ASK modulation demodulation MATLAB code?

My MATLAB code linked below implements ASK modulation of an M-ary signal, impresses it on a carrier, adds AWG noise of various SNRs. Then, for each SNR, demodulates the signal and calculates the ...
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71 views

Implementation OFDM system in Matlab

I am working on the OFDM transmission system. A channel is given, MR x MT; input data MT x S, and length of a cyclic prefix (CP)....
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1answer
68 views

Complex output after inverse FFT of a real signal

I have a real one dimensional signal s (light absorbance in a flow cell), which has significant noise and some periodic noise after performing a deconvolution of $S$ from $S_o$. Basically fft($S$) was ...
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27 views

Is it possible to recover the time-domain signal after manipulating it in the frequency-domain? [duplicate]

I've worked a fair amount with EEG signals, though I've never had formal training in signal processing, so please excuse my ignorance. The problem is this: my signal has noise at many, many ...
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1answer
29 views

Numerical higher order derivatives and time axis

I have a rather elementary question. Suppose we wish to study even-derivatives of an instrumental signal say second fourth and sixth derivatives and plot it as a function of time. With each successive ...
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2answers
52 views

Matlab - Bode plot of Lag Filter + Integrator

I am rather new to Matlab and I just cant make sense of what I see in the bode plot of the continuous and discrete version of the same function. The bode plot of the continuous function looks as ...
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1answer
45 views

Are MATLAB function zp2tf() and tf2zp() are complementary or not?

I was under impression that given, pole, zero and gain the transfer function (filter coefficients b and a) is fixed. Therefore, ...
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2answers
27 views

Plotting impulse functions on the same time axis with other functions in MATLAB

I am trying to plot the following function: I have to plot another function along with it all on the same plot. Got the other function working, but I can't seem to get this one working. The code ...
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2answers
77 views

Shift vector function in MATLAB

I am working on my own shift vector function that will be used later to compute the convolution of two signals. The function has to shift the vectors either left or right depending on the magnitude ...
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1answer
38 views

How to implement Matlab welch in python with the same result?

I want to implement Matlab pwelch function in python. The Matlab code is shown blew: [PSD,f] = pwelch(data,length(data),[],[],2000); which data is a row vector ...