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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27 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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27 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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power spectral density estimation

I have an audio signal carols.wav. How do I obtain the PSD in Matlab using the inbuild pwelch function and also to write my own code.
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2answers
21 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
36 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
20 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 ...
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1answer
37 views

Is it possible the difference between OFDM-CP and OFDM-ZP about 10dB

I'm building basic matlab code for ofdm, but when I change the CP OFDM into ZP-OFDM with sme parameters, I get the performance is worse by up to 10 dB!! Is that right ? or there is some thing wrong in ...
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21 views

Underwater acoustic channel is giving me a flat BER vs SNR curve

I need to do OFDM and GFDM signal transmission in underwater acoustic channel. I have my underwater acoustic channel as follow. ...
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0answers
11 views

What ICA should be applied?

I am using ICA from EEGLAB toolbox (not sure if I can use MATLAB's RICA() function as well). I am trying to use Infomax or JADER ICA to seperate two sources which transmitting at a carrier froquency ...
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1answer
39 views

Low pass filter output showing instability

I am fairly new to DSP, and I'm trying to implement the Pan Tompkins algorithm for QRS detection of ECG signals in MATLAB. The first stage of the algorithm consists of a second-order low-pass filter. ...
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1answer
36 views

Filtering in the Frequency Domain - DIP [closed]

I am trying to do some filtering with a gray scale image in the frequency domain. I am just getting into matlab after some time away from any signal processing or coding and can't quite seem to get my ...
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1answer
32 views

Finding the phase and frequency of a tone with Doppler. What is wrong in the code?

I am trying to find the phase and frequency of a single tone having a small Doppler (10 Hz). I have the following code. The integration time for the operation (the length of the time vector) is ...
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2answers
49 views

Sampling frequency of voice and audio

I read somewhere that the signal of speech has a bandwidth from 300 - 3400 Hz(Why), and audio files have a bandwidth from 50 Hz to 50000 HZ(Why). Could someone help me , why are those constant ...
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3answers
183 views

Labview vs Matlab? Which one better for image processing?

I want to learn practical image processing from scratch/basics. Which software will be helpful in this regard? Matlab or Labview?
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13 views

Different images between MATLAB and ImageMagick

I'm using ImageMagick 7.0.8-64 Q16 for Windows and MATLAB R2019. I'm doing the same operation (resizing with bicubic interpolation method) in both programs. ImageMagick code: ...
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1answer
22 views

What is meant by 'combine the luminance and chrominance '

I am new with image processing. I'm trying to implement a research paper in MATLAB. I didn't understand a sentence. Here it is: The luminance is enhanced by applying the proposed algorithm and it ...
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1answer
82 views

Autocorrelation of a uniform random process

i am currently learning the basics of signal processing. As you may know the definition of the autocorrelation is different if you look at a random process or for example a deterministic signal My ...
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1answer
61 views

windowed sinc filter in matlab

Hello i'm designing a low pass filter windowed sinc in matlab ...
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0answers
10 views

Problem implementing KL expansion with square-exponential kernel: output just looks like Gaussian

I am trying to implement the Karhunen Loeve expansion for a 1-D Gaussian random field with a square-exponential kernel. Specifically, I know that a Gaussian process has a KL expansion $\hat{U}=\sum_{...
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0answers
21 views

Taking transfer function out of real heating system

I have some king of heating system: heater (that I can control current for final power control) and a thermocouple (for measuring the temperature). I also have a device that can record temperatures ...
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1answer
17 views

Set of all images with a certain MSE between themselves and a given image

Mean squared error between two $M\times N$ images, $I[m, n]$ and $D[m, n]$ is defined as: $$ MSE(I, D) = \frac{1}{M\times N}\displaystyle \sum_{m=1}^{M}\sum_{n=1}^{N}(I[m, n]-D[m, n])^2 $$ For a given ...
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1answer
37 views

High order IIR Comb Notch Filter with small Bandwidth - Low atenuation of harmonics

Im filtering an EMG signal, more precisely the 50 Hz frequency and its harmonics. For that, I've constructed a comb notch filter (on filterdesigner in Matlab), with its fundamental frequency being 50 ...
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1answer
33 views

What determines peaks in FFT?

I ran FFT on three audio files and found that the results for some have more peaks than the other. Could anyone give me any conceptual explanation as to what determines these peaks? Below are plots of ...
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0answers
6 views

Calculating Error Band Around Signal Line

I am using Matlab 2018b and trying to plot a dynamic transparent error band around a signal line. Below is the code I am using. Below the code is the Matlab error message I am receiving as well as ...
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5 views

How to make SL to RF inport in simulink work real time?

I am using qam in the simulink and need to upconvert the complex baseband data and obtain the time domain passband signal. I pass the complex baseband data to SL to RF inport and then do the ...
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0answers
25 views

Skew measurement with phase deviation

I am calculating the standard deviation of skew (= phase/2*pi*fin) from the 1000 monte carlo runs of the following code. In the y0, there is no input skew., but in y1 there is a skew present. Its ...
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1answer
77 views

what is the theory behind Butter function?

I want to understand why this code used tan and cos ? ...
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1answer
25 views

channel gain calculation

I want to calculate the SINR term in an up-link of wireless communication system but there is different models for simulation. I want to know what is the exact meaning of |h|^2 in this formula: SINR = ...
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15 views

I need to insert an underwater acoustic channel model to an existing code that compared between OFDM and GFDM

The acoustic channel model that I have will output the channel impulse response. However, my signal is modulated in frequency domain (by doing fft). Hence, I want to obtain a frequency response of the ...
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1answer
53 views

Compensate delay of non-symmetric (non-linear phase) filter

Lets assume I want to apply a matched filter h which is non-symmetric to my signal x and the output is ...
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2answers
56 views

How to filter data with given numerator and denominator coefficients of an IIR Filter, in MATLAB Implementation

Coefficients are: b = [9.02201251375918 0.485095309463300 -0.571759308660462 3.63774928924158 4.42592447788520 1.30093840271037 -0.898592924453941 -9.08965268561448 -12.4939309921467 ...
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1answer
52 views

How do I process IQ data received from a signal analyzer

I used a signal analyzer to get IQ sample data from a blue tooth device. The IQ data received is in the form of a .MAT file and I examined the file contents and see an + ibn samples where a, b are ...
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18 views

What is the meaning of these Fixed Point Properties e.g.CustomSectionInputDataType?

I was trying tom implement a Butterworth filter and i came across a example on Mathworks site which emphasizes to customize various terms related to the filter. Following are some of the terms i could ...
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19 views

On the use of OMP for sparse channel estimation based on pilots

Given an OFDM frame whose length is 256 sub-carriers, the length of guard interval CP is 64, and the transmitted known pilots 'in red' are 64 too as below: where the received signal is suppose to ...
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1answer
24 views

Block by block CCDF and PAPR analysis in MATLAB

There are few signals (OFDM-like modulation scheme with uniformly distributed data source) generated by my script. I need to compare scheme performance in sense of CCDF (Complementary Cumulative ...
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19 views

What is scale ambiguity in computer vision?

When you compute relative pose between cameras, translation is only accurate upto a scale. Need some help in understanding the scale ambiguity and what exactly does it mean translation is accurate ...
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2answers
60 views

Hilbert transform with strange behavior

I am taking the Hilbert transform of a signal in Matlab and I don't understand part of the result. Below are the complete signal $z(t)$ and phase $\phi(t)$, obtained with ...
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0answers
17 views

Detection time of a spur using FFT?

Say I have the following parameters, NFFT=2^14 Fs= 50 MHz main signal @ 22 MHz and its alias at 28 MHz at signal power -40 dbfs and a spur @ 2 MHz and its alias at 48 MHz Leave aside the alias's. ...
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3answers
56 views

Phase of the DFT

I'm new to the numerical processing of sampled measurements so my question is probably trivial. Let's suppose that I have the following sampled signal generated in MATLAB: ...
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0answers
17 views

lte matlab baseband IQ recovery

I am a beginner again to signal processing, I did my degree over ten years ago, and I am relearning all my signal processing stuff. I am a software developer by trade but now I am looking at some LTE ...
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1answer
86 views

NCO loses lock after a while for certain values of alpha

EDIT: So the transfer function for my system is $$ F_{nco}(z)=\beta E(z)/(z-1)$$ $$ z\Theta_{nco} (z)=\Theta_{nco} (z)+\alpha E(z)+\beta E(z)/(z-1)$$ So I would like to obtain $\Theta_{nco} (z) / \...
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2answers
175 views

FFT of triangular wave

I am new in dsp.. so please bear with me. I want to plot FFT of a triangular wave. I am using the code below to first generate the triangular wave and then take its FFT ...
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1answer
26 views

Calculate Frequency/Period from Output of a Maximum Entropy Spectrum MATLAB function

When I plot said function output, "p," it looks like a typical spectrum with an easily identifiable peak at a given ix on the x axis. The help rubric from the function is ...
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3answers
79 views

Matlab IIR cheby2 bandpass, problems with Magnitude

I am trying to implement an IIR bandpass in Matlab. There are two things I don't understand. But first of all, let me post the code. ...
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1answer
59 views

Why does my sinusoid look “AM” in shape?

My code is : Fs=200e6; Ts=1/Fs; NFFT=2^14; Runtime=(NFFT-1)*Ts; t=0:Ts:Runtime; f_in=90*1e6; y_in=sin(2*pi *f_in *t); plot(t,y_in) ylim([-1.5 1.5]) Then why does ...
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1answer
22 views

Matlab applying an FIR filter to a signal, generated in Matlab

I want to create an FIR in Matlab and apply it to a signal (also generated in Matlab). You will find the code below. I will put my questions in order from here. 1) The filter coefficients vector "b" ...
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1answer
31 views

FIR Filter Type - MATLAB

A question about using fir1/fir2/firpm to design FIR filters in MATLAB. The first parameter is the 'filter order'. For my filter design I pass in 250 as this argument. However, when looking at the ...
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32 views
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27 views

MATLAB fir2 - npt and lap

This might not be the right place to ask this, but I'm hoping someone can explain two of the arguments in the MATLAB fir2 function. It is a function for designing ...
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1answer
27 views

Why reprojection error is minimized instead of triangulation error for bundle adjustment?

For bundle adjustment optmization why is reprojection error minimized instead of traingulation error or ray-to-3d point error? Disadvantage with reprojection error is: for perspective camera, its ...