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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Problem with the output self implemented “ Iterative FFT DIT Radix2 ” algorithm matlab

I´m trying to implement my own FFT with the iterative Radix2 algorithm (I even thought about using the recursive one but it seems Simulink doesn´t allow me to). I tried all of the possible variations ...
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Strange result in simple LPC simulation of a sinus

I'm trying to understand how Matlab LPC function works. So I made a little example script : I generate a real cosinus, calculate the LPC coefficients of this signal and then I try to predict the ...
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how to convert the zeros of an odd order Chebyshev Type II from low-pass prototype?

My DSP book (Rabiner, Lawrence R., and Bernard Gold. "Theory and application of digital signal processing." Englewood Cliffs: Prentice-Hall (1975).) has the following transformations for ...
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How to Equalize 2 columns I & Q data of the 16 QAM constellation?

I need help regarding the I & Q data which I extracted from VPI simulation software. The data is for 16 QAM constellation which is distorted by chromatic dispersion. The data is in 2 columns and ...
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Calculating threshold in white noise for multiple pulses

I want to calculate the threshold for a given probability of false alarm (PFA) in a system, in which the noise is given by a coherent summation of three white Gaussian noise signals. Of course, there ...
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Design an FIR filter [closed]

How I can generate a signal with three sinusoidal components at frequencies of 50, 75, ,100 Hz, and 150 Hz). Then design an FIR filter to keep the 75 and 100 Hz sinusoids and get rid of (remove) the ...
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Frequency Domain Represenation of Time Domain Signals [closed]

What is the inside of converting the time domain axis to frequency axis, as you can see in the last line in the given code? When plotting graph in frequency domain we need to convert the time axis to ...
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1answer
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Estimate and Track the Amplitude, Frequency and Phase of a Sine Signal Using a Kalman Filter

There is sinusoidally controlled signal, which other than being noisy, can change values for amplitude, frequency, phase and offset. At every new sample a new sine is fitted for the last N samples. ...
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denoising and debluring [closed]

One of the many applications of Internet of Things (IoT) consists of continuous monitoring of temperature in an area. To that end, several temperature sensors are installed at different locations. ...
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1answer
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Results do not match between manually computed PSD values and those from MATLAB pwelch function

The power spectral density (PSD) of the given input signal $x[n]$ is computed as follows: ...
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3answers
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Why Matlab Spectrogram of slow and rarely sampled signal shows high frequencies

I have a signal, which was measured for 14.4 minutes (= 864 seconds). There are 192 measurements, so one measurement was done in every 4.5 seconds, which results in a 0.22 Hz sampling frequency if I ...
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How to find the number of vectors to sample in Compressed Sensing?

When comparing my MATLAB code to a previously written one, I come across the following formula for the number of vectors to sample: ...
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Frequency response of a moving average filter/box car

I have designed a simple filter for an embedded system handling magnetic field data. The incoming sample rate is 128Hz from the sensor and we have output data rates of 1Hz, 16Hz, 32Hz & 128Hz So ...
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1answer
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What does it mean for a transfer function to have multiple sets of zeros in the numerator?

I was looking at the source code for Matlab's tf2ss function and I noticed that it parses the numerator assuming that it is a matrix, not a vector. So I looked at ...
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1answer
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Different formulations of Chebyshev II resulting in different poles?

I am currently trying to implement a C++ program to calculate digital filter coefficients using a Chebyshev Type II filter design technique. The text I am using to understand the theory of the ...
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1answer
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how does wavelet transform detect pulses from a signal

I am learning wavelet transform, below image is an example I have that uses haar wavelet for decomposing the simple haar wavelet like signal. i know that the coefficients at each level are results of ...
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1answer
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How to identify from poles and zeros if it is a bandpass

For an example, this is a figure I made from MATLAB, based on the poles and zeros, how can identify if it is a bandpass filter.
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1answer
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Clip-on tuner signal analysis

I am new to this forum and I hope you guys can help me. I am sampling vibration signals when I pluck a string from an electric guitar using a max4466(https://www.adafruit.com/product/1063) mic glued ...
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A scaling difference between MATLAB's pwelch and Python's SciPy welch

I'm having trouble in python with the scipy.signal method called welch (https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.welch.html), which ...
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1answer
43 views

Find coefficients of optimal Wiener filter of length 2

I need to find the coefficients (impulse response) of a FIR Wiener filter with length equal to 2. I have a gaussian white noise signal that is generated using the Standard Normal Distribution (mean = ...
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1answer
54 views

Why is the Fourier transformation full of spikes with 12.5 Hz frequency steps?

I am performing a fourier transformation in matlab for time signal data with monitoring points for pressure extracted from a simulation. What I get at the end is a spectrum as shown below: I am ...
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1answer
56 views

How to calculate the SNR from the data collected by ADC?

I want to design a filter to deal with periodic signals according to the actual collected data. In practice, I would like to use the SNR as the criterion to judge the performance of the filter. ...
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1answer
81 views

Estimate the time delay of two signals

I am having 2 sets of data data1 and data2 .I wanted to find the delay between the two datasets. Assume data1=[1 2 3 4 5 6 7 8 9 10] and data2=[0 0 0 0 1 2 3 4 5 6].From the data I know that, data2 is ...
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2answers
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Can we use Gardner timing error detector for multi level QAM or OFDM systems? [duplicate]

Sampling frequency offset (SFO) between the transmitter and the receiver in any system causes a gradually increasing timing error which is seen as an increasing phase rotation (function of time). In ...
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Transfer functions for Scipy and Matlab's Butterworth filter don't seem to match theory

The squared transfer function for a Butterworth filter of order $n$ should be $$ |H(f)|^2 = \frac{1}{1+\left(\frac{f}{f_c}\right)^{2n}} $$ where $f_c$ is the cut-off frequency. (Here's one of many ...
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2answers
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Matlab Pade approximation influence on bode plot and step response

I would like to approximate a delay via the pade approximation. I set a normal delay via the exponential term and I set a delay via the pade approximation and I look the difference between the both ...
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2answers
55 views

Impulse response of linear interpolation in discrete time

I'm trying to understand interpolation in discrete time. We know that for linear interpolation we use h(t)=triangle waveform. When we talk about linear interpolation in discrete time, I'm using ...
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1answer
37 views

Ideal Allpass filter

Is it possible to implement an ideal allpass filter in Matlab? The filter response should be like this: Note: the photo is imaginary (I did it using paint).
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1answer
37 views

How can I add complex WGN to a complex damped signal for a specified SNR?

I want to add complex wgn to a signal for a specified SNR. I have been using the following lines: ...
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1answer
116 views

How to Solve the Image Dehazing Problem Using ADMM?

I want to solve the image dehazing problem using ADMM. I want to use the proximal algorithm to optimize each element. I refer to this treatise: Efficient image dehazing with boundary constraint and ...
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1answer
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Does Maximum Likelihood detector (QAM symbol detection) enhance BER?

Assuming QAM symbols (or OFDM system) with AGWN, I found that the use of ML detector does not enhance the BER but only enhances (reduces) error vector magnitude (EVM) because of symbol decision and ...
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1answer
38 views

Wrong number of samples per symbol for BPSK in MATLAB?

Goal is to achieve 8 samples per symbol for BPSK signal. After analyzing the plot of below code, IMHO its not 8 sps, I am right? If yes what I do wrong? ...
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1answer
100 views

1ppm Sampling clock offset in Matlab

How to emulate a sampling clock offset (between the transmitter and the receiver) of 1 part per million (SCO=1ppm) in Matlab? Theoretically, I can upsample the signal by a factor of 1,000,001 (one ...
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1answer
31 views

Phase Error Growth in Digital Mixer Signal

I am working on a code where digital mixing is to be performed for down-conversion of incoming signal. The mixer signal is created using the phase accumulation approach. However it was observed that ...
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2answers
90 views

Deconvolution of system response in Python/Matlab

I had two sets of data, the output function of the system (time series with a length of 1292 entries) and the transfer function (similar to a gaussian with a length of 681 entries). I would like to ...
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1answer
67 views

How to Solve Blind Image Deblurring with Total Variation (TV) Prior Using ADMM?

As a continuation of the question How to Solve Non Blind Image Deblurring with Total Variation Prior Using ADMM? I would like to understand how could one solve the Blind Deblurring (Deconvolution) ...
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fft result with the number of integer multiples of fs

With the cosine signal fc=3Hz and the fs=13Hz as below, fc=3; fs=13; Ts=1/fs; N=101*13; % 101 times of fs n=0:N-1; x=cos(2*pi*fc*n*Ts); and then fft with the ...
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1answer
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How to Solve an Image Deblurring Problem by Variational Methods Using ADMM?

Following up on a previous question, I wanted to understand how to solve an image deblurring problem using Variational methods in matlab or julia. Given some original blurry image $f$, I would like to ...
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Laplace transform plot isn't right

I'm trying to plot the Laplace transform of a function. Here's my MatLab script ...
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0answers
62 views

Plotting amplitude and phase spectrum in MATLAB [closed]

We are supposed to write a code that will help us plot the following signal and their amplitude and phase spectrum. unit step exponential unit ramp sinc rectangular I believe I can scrap the code ...
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2answers
45 views

unsymmetric fft in matlab

This is the FFT of a 4khz sin signal. I wonder why the negative part and positive part of X axis is not symmetrical? ...
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1answer
54 views

How to find the minimum order for a low pass filter with different gain levels

I have the following for a filter with passbands having different gain levels, in this case I set the order arbitrarily to 100. Is there a way to find the minimum order that still satisfies the ...
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1answer
90 views

How to Solve Non Blind Image Deblurring with Total Variation Prior Using ADMM?

How could one use the Total Variation frame work to solve the Deblurring problem? Specifically using the ADMM as a solver. One could assume the blurring operator is known, linear and shift invariant. ...
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1answer
62 views

Magnitude Spectrum of a Linear Chirp Signal

I am trying to understand intuitively the fft of a signal that changes in frequency in time. Suppose I have the fft of a linear chirp signal sampled at 1 kHz for 2 seconds. The instantaneous frequency ...
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1answer
58 views

Combining two wave generation formulas does not work as expected (MATLAB/OCTAVE)

I'm trying to convert sawtooth wave calculation formula to Octave/Matlab language. Here are the original formulas. My Desmos take is here. I've got formulas for triangle wave and square wave working ...
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2answers
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How to multiply two FFTs in MATLAB?

I want to find the output signal(y) from input signal(x) and impulse response(h). To do that first I take the fft of both x and h, then multiply them, and finally taking the ifft of the result. The ...
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1answer
31 views

Multi-statelevel detection

I'm trying to develop an automated state-detection algorithm, basically expanding on MatLab's "statelevels" function to multiple (i.e. 3+) states, however I've hit a brick wall in trying to ...
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1answer
34 views

Trying to do frequency analysis of an accelerometer output

I am new to signal processing. I have a 3 axis MEMS accelerometer. I have read its output into $\mbox{Matlab}^{\tt TM}$. My problem is that the signal I am trying to isolate has a frequency of about 0....
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1answer
37 views

Where can I get the file l1eq_pd.m?

To recover the original signal when compressive sensing is used, we get an error, to avoid the error, we need to modify the l1eq_pd.m file. How to go about it? Where can I get this file in Matlab?
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How can I define x(t) in terms of n?(matlab)

I have a signal x[n], that is sum of two sinusoidal signals. $x(t)=sin(2𝜋100t)+0.7cos(2𝜋500t)$ ...

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