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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11 views

Why does the flat part of the BER curve appear after the Viterbi decoder (MatLab)?

I am trying to implement convolutional codes according to this MathWorks example in MatLab 2014a. ...
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Morse / Morlet wavelet relationship?

Does anybody know what the relationship between Morse and (complex) Morlet wavelets are? I'm looking at images in papers about the Morse, and it looks like a Morlet to me. Is the Morse a ...
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psd in matlab, problem with the coefficient $\frac{1}{2\pi}$

Using the fft to mimic the Fourier Transform I have this question. The definition that I use for the PSD $S(f)$ is: $S(f)=\frac{1}{2\pi}\int_{\infty}^{\infty}exp(-i\tau2\pi f)r(\tau)d\tau$ where r(t)...
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Calculation of PSD using Hamming Window

I have 600000 time domain Data. I want to calculate the psd using that data. But I want to use hamming window to my data set and overlapping them to get a smooth psd vs. frequency graph. I need a ...
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15 views

How to implement codebook of modulation

I need to perform the given algorithm for different types of signal modulations: BPSK, QPSK,16 QAM... Let's assume a system:$$ Y=HX+N,$$ $X$ is receive signal/data, $Y$-transmit signal/data, $H$- ...
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How can I detect the tree rings?

I'm looking for the way to detect the tree rings automatically in the wood dist image. Using the matlab, I have removed the background, and binarized the image. How can I detect the white and black ...
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Questions about Optical Flow implementations

I have some doubts related to some of the optical flow implementations. How to compute angular error for optical flow algorithms? I know the formula for computing, $\theta=\arccos(\vec{v}_c\cdot\vec{...
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CoeffFracLength negative or larger than the CoeffWordLength [Fixed-Point Filter Properties in Matlab]

I have been reading the fixed-point filter properties in Matlab and I have found that the parameter "CoeffFracLength" can be either zero, negative or positive. And also, it can be larger than the ...
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38 views

Estimate amplitude of signal between 45 Hz-60 Hz

I have to estimate the amplitude of vibration of a real world robot. The signal is originating from a laser distance measurement, and the vibrations are somewhere between 45 and 60 Hz. I'm using ...
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1answer
32 views

Ways to differentiate three respiratory signals

I have three 1-min respiratory signals I derived from ECG signals. I am wondering if you guys have any suggestion on differentiating those three? The red line represents the experimental signals and ...
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Implementing Costas loop for 4-PAM

EDIT: I've tried a different way of implementing it http://read.pudn.com/downloads80/doc/project/307210/CarrierRecoveryUsingaSecondOrderCostasLoop.pdf and I keep getting the same result, depsite the ...
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1answer
65 views

MATLAB FFT Amplitude

I am trying to understand FFT, DFT through Matlab and I am fairly inexperienced in all of these. I have a time vector t and a corresponding simple sine wave x = 0.25*sin(t). Now I would like to view ...
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2answers
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Where can I find information about how to implement IIR filters on micro-controllers?

I am trying to implement an IIR filter on a LPC1769 (I don't know if it's relevant). I already have the H(z) so all the design part is prety much solved. What I am looking for is information about: ...
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1answer
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bibliography about implementation of IIR filters

I need to implement a 6th order IIR filter. The filter I need to implement is the A-weighting. I've simply used the bilinear function of Matlab with an fs of 20Khz. I need to implement this over the ...
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1answer
34 views

Using fourier coefficients to reconstruct data in matlab

When doing a discrete fourier transform on some data using matlab's fft function, its output is a set of fourier coefficients but I was wondering how do I go about converting these into an and bn so I ...
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1answer
28 views

Validating Jakes model in Rayleigh Fading channels

I am trying to validate the Jakes model by comparing the autocorrelation function given by $ \rho(\Delta t ) = J_{0}(2 \pi f_{d} \Delta t)$, where $ f_{d} $ is the maximum Doppler shift, $ J_{0} $ is ...
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A question about Fourier transformation

Hello, this is my first time actually asking in stackexchange. I am a computer engineering student and currently i am doing a linear system course (i don't really know how this is equivalent in ...
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Notch filtering minimizing artifacts in signal

I have to notch filter the following signal As you can see it is a signal with really high amplitude.And this causes me a lot of problems. I've designed a bandstop filter (46-55 Hz).The MATLAB code ...
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Quadrature demodulator. Relationship of sampling rate and error

Task: to estimate the frequency of the power grid signal. I use a quadrature demodulator. I get the I / Q components. I calculate the angle (phi = atan(Q / I)). I differentiate the angle and get the ...
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Question about FMCW range-velocity plot

I am working on plotting range-velocity heatmap of the receiving FMCW signal. I actually have already plotted. However, I do not really understand the mapping relationship between Doppler FFT bin and ...
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29 views

Double Sided FFT Power Spectrum on Matlab

I'm trying to plot the power spectrum of a signal but I cannot understand clearly the units of the amplitude. ...
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1answer
58 views

Is there a good method to extract a reference sin/cos from a group of signals?

For the removal of a pure interference from a group of sampled signals, if I know the exact frequency of the interference I can simply use an I/Q demodulation technique (i.e., a phasor projection) to ...
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1answer
54 views

Designing an FIR filter in Matlab with differing number of precursor taps and postcursor taps

I'm trying to fit an FIR filter to the measured frequency response (magnitude and phase) of a device. The frequency response is essentially a low-pass filter. I'd like to vary the number of taps to ...
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Tracking a signal

I have two signals representing steering wheel angles, one representing the driver’s inputs (red), while the other one represents the system’s reference signal (blue). I want to estimate in real time ...
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Matlab time serie mat file format

I'm trying to find the ideal data exchange format for our signal processing data. I've tried various formats like csv, wav (unsuitable), UFF, tdms, but there always seems to be some guy saying "don't ...
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fft and inverse fft error size and applying impulse response matlab

I have a signal called noise. I am using the following command to calculate the mean squared error after fft and inverse fft process: ...
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23 views

additive white Gaussian noise -ask fsk psk

i want to simulate a system that uses ask,fsk ,psk in Matlab with additive Gaussian noise for each mode . figure shows the system propti and Eb/N0=6db my question is how to calculate the standard ...
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How to calculate splines of different order under MATLAB?

I am trying to compare spline interpolation of different order to show that Cubic is working better. Is there any toolbox or so to spline interpolate points between knots?
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37 views

How do I narrow the frequency from a time domain Gaussian signal?

I'm trying to get a frequency domain Gaussian signal that starts from 180.045 THz and ends in 180.65 THz. This is the matlab code I used to get the FFT of time domain Gaussian signal: ...
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How to measure SINAD of an audio signal?

I tried to measure the SINAD and SNR of a recorded audio signal using MATLAB. The following is the process I did to measure the 2 parameters: Firstly, I generated an FM modulated signal(1 kHz audio ...
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1answer
82 views

Amplitude demodulation of sinusidal signal in matlab

AM-demodulation task and I was asked to demodulate the signal in MATLAB and the result should contain three pictures. plotting the $fft$ the (frequency spectrum)of the signal i was able to determine ...
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1answer
25 views

MATLAB Image-Processing Toolbox: asking for a roadmap!

I plant trees in the north of BC for a living and have next to none sp experience, please be gentle :^] TLDR: The problem is essentially this: tracking and calculating the "height" of three ...
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1answer
48 views

Machine learning for denoising MRI images

I'm currently a sophomore in college and pretty new to the field of research. I'm currently working on an existing algorithm for MRI denoising and the results are nothing that great. I can't see how I ...
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Discrete Fourier Transform by longhand using MATLAB - what is the lower limit for N?

I'm seeking some guidance/reassurance on my understanding so far of the DFT, as demonstrated by my MATLAB script below. I deliberately compute the DFT longhand. My first question: Are my ...
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2answers
36 views

What do the 1D filters represent when using imfilter?

I am reading the source code of an algorithm that is used to process an image. While reading this source code (and others), I've found lines of code of the form ...
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1answer
36 views

Fourier Transform within a certain Limit

I want to evaluate fourier transform within a certain limit in MATLAB,the expression of which is $$X(f) = \int_{1}^{4}{x(t)e^{-i2\pi ft}}\,dt$$ I have to find value of the above expression ...
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2answers
42 views

Filtering Surge Signals

I am working on a matlab program which needs me to detect the pattern of surges in a signal and then remove them. I tried out various filters like median, hampel, butterworth etc. but couldn't get an ...
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2answers
24 views

How to extend line until end of image

Lets say, i have a line and i want to extend the line until the end of the image. The line is displayed in the first photo with the green is my basic line, i want to extend it like the second image, ...
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1answer
32 views

Plotting phase delay from first principles giving different result from phasedelay() function. Why?

I have a length 10 Finite Impulse response as shown below, and I am trying to find the phase delay of this FIR. $$h[n]=\begin{cases}0.1,& 0\le n \lt 10\\ 0,&\textrm{otherwise}\end{cases}$$ I ...
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Finding gain on root-locus

I have to design a compensator using root locus for the system $G(s) = \frac{1}{s\cdot(s-4)}$ that follow the following criteria: $op\% \le 5\%$ $t_{2\%} \le 4s$ So I started computing $\zeta$ and $...
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Frequency selective channel modeling using rayleighchan object in matlab

I intend to model a frequency selective channel using matlab "comm.RayleighChannel" object. Consider the following command, which sets the parameters of Rayleigh channel : ...
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How do I filter out the specific components at 20MHz, in this figure?

I used the filter builder (lowpass) , to cut off the frequency at 0.5 MHz, and thus used a stopband of 0.1pi, and a passband of 0.0125pi. (Sampling Frequency= 80MHz). However, the output was still ...
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Plot Frequency Spectrum of Binary Sequence in Matlab

I am new to Matlab and I am trying to implement a section of a published paper, the basic idea of the part that i am implementing is to show the frequency spectrum of camera aperture. The shutter ...
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1answer
36 views

Hilbert transform of symbolic function in Matlab

I have a signal of the form $f(\omega,x) = g(\omega) e^{i \omega (x +c)},$ for $g: [\omega_1 , \omega_2] \rightarrow C, \, x\in R$ and some constant $c.$ I want to get the function $$ F (\omega,x) = \...
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1answer
59 views

How to get maxima of rho in hough table

i applyed hough transform in my image and this is the result of hough table, i must get the maxima of rho in two basic angles of theta , the one is around -65 : -60 and the other is round 30:35 How ...
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38 views

Notch Filter with given Bandwidth

I have to use Matlab with the iirnotch()-function to design a notch filter. The notch should sit at 520Hz, the Bandwidth should be 100Hz and I have a sampling ...
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1answer
39 views

How to design a a filter and how to determine the poles and zeros on the basis of following informations?

A sinusoidal signal of 300Hz frequency,3V amplitude is contaminated with line frequency (50Hz,1V). Design a digital filter including poles and zeros to remove the interference component. Consider the ...
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1answer
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How to separate silence from frequencies in Matlab

For a project, I was asked to create a DTMF detector on Matlab. I know that the audio sample that will be provided will have 4 tones maximum, possibly less, and that the audio begins with a 0.1 second ...
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Designing Matched Filters on Arduino

I'm trying to develop a prototype at the moment that includes a sensor to detect how fast someone is typing on a keyboard. Essentially this sensor is a microphone that will be able to detect keyboard ...
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How to generate wireless O-QPSK modulated signal in Matlab?

I am trying to create a small simulation where I would need to transmit a wireless signal from one wireless node to another and then transmit one more message back to node 1. Considering this is LR-...