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 stop matlab from rounding my values and keep them at same precision during calculations?

here are my IIR coefficients: CoefIIR=[1.630078934734 1.267893338385 1.112390120011] and here are the result given to me by matlab commands: ...
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finite precision vs infinite precision?in terms of quantization in ADC?

What is difference between finite precision and infinite precision?? I think analog(continuous) output(y axis) amplitude signals are referred to have infinite precision while discrete output amplitude ...
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SAR processing images fft with Matlab

I am investigating processing of SAR images right now, it is new for me. From Magellan images (1024x1024), I have to determine the Doppler Centroid. For that, I have to compute the azimuth spectrum (...
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80 views

How we can quantize a sampled signal in MATLAB?

I have a continuous time signal $x(t)=\sin(2πft)$ where $0 \leq t \leq 3$. I want to sample the continuous time signal and then quantize that sampled signal and then plot both sampled and quantized ...
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48 views

sampling a continuous time signal using MATLAB?

I have a continuous time signal $x(t)=cos(2 πft)$ where $0\leq t \leq 2$. I want to plot discrete time signal $x(n)$ where $0 \leq n \leq 19$ for sampling frequency 100 Hz and signal frequency 10 Hz. ...
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Audio in Image,Graph or WaveForm Representation

Our task is to feed the audio data into the deep learning tensor flow model in the form of image representation(or graphical,waveform). Question is what is the best way of representing audio in image ...
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1answer
40 views

MATLAB: Applying Inverse Fast Fourier Transform to an array of real numbers

I'm trying to understand the difference between applying the Discrete Cosine Transform (DCT) and the Inverse Discrete Fourier Transform (IDFT) to the log Mel-filterbank energies as explained in the ...
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35 views

Torque signal fft

I have the following torque signal picked up with a 10.240Hz sampling rate from a testbench. I am studying its fft which I create on Octave with the following code: ...
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16 views

Duration of a signal using matlab [closed]

I'm trying to determine the duration of a certain signal(keypad tone) and the pause between each tone in a sequence of tones. The data has already been converted to a discrete array of data. My ...
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Relation between PDP (Power Delay Profile) and channel impulse response

I am traying to perform a simulation in Matlab and I faced up with some practical/theorical problems. The channel I want to simulate is frequency selective fading. The packets are short compared with ...
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Extracting different frequency bands (alpha, beta, gamma) from brain activity data

I am new to signal processing and despite googling about my question, I still couldn't find the solution. I have an Electrocorticography (ECoG) dataset. This consists of recording brain activity from ...
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Power of ICI in OFDM System

I am studying the effect of time offset in OFDM system, I am interested in calculating the power of the ICI on each subcarrier, I am a bit confused about how to do it in Matlab, so how can I measure ...
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How to create a synthetic time series where power spectral density estimation is achieves better results than a direct Fourier transform?

I am trying to create a synthetic time series where PSD estimation is necessary and useful to recover the correct spectral information of the time series. But so far I can only create a time series ...
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23 views

shannon interpolation in image processing

I tried to implement Shannon interpolation on a 2D array. First, implemented it on a 1D signal, just for sanity-check: ...
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20 views

Cancelling effect of a system on a signal

I have a signal $A(t)$ and it's been transformed using an unknown system to a signal $A'(t)$. I also have another output signal $B'(t)$ from the same system and I want to retrieve the corresponding ...
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1answer
32 views

Difference equation with variable coefficients in MATLAB

Given the following difference equation $$y[n]-\left(\dfrac{n}{n+1}\right)y[n-1] = n\cdot x[n]$$ How can we use MATLAB to solve it? I know if the coefficients are constant we can simply use ...
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21 views

Help needed for Matlab Spectrogram plot

I am trying to plot a spectrogram using Matlab. Basically what I need is to have: -time in the X axis -Velocity in Y axis -Intensity is the current (in pico Ampere) Basically, I want to create a ...
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25 views

Time variant frecuency selective fading in matlab

I am traying to simulate a frequency selective fading channel in Matlab and I have faced with some issue/questions during the implementation. It is a DSSS (BPSK) modulation and the code is organized ...
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62 views

What does it mean to plot a PAM signal over a number of symbols?

Our course has been using the book Introduction to Communication Systems by Upamanyu Madhow for our communications course. There is a question in the book on page 87 Software lab 2.1 which is ...
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Deconvolution of an Image Acquired by a Square Uniform Detector

So, I acquired some images by scanning a radiation source with a square detector like in the following gif. Where the dashed grid represents reality, the 3x3 square my detector, and the 4x4 my ...
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Frequency domain channel coefficients in OFDM

I want to find frequency domain channel coefficients in OFDM in matlab. The channel is multipath rayleigh in nature. I had tried the following code but not getting the results. ...
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29 views

How should I model my low-pass filter to get best SNR of a peak?

So, I'm trying to understand how to use a low-pass filter and optimize the cut-off frequency while getting the "best" amplitude of a peak I am interested in. I have attached picture 1 which shows the ...
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51 views

Removing DC Offset (via removing mean) of input and output signals affects their coherence

I have input $x$ and output $y$ signals (fs=10 Hz, length N=10800). I have removed DC offset via the following equation: $x_{normalized} = 100 \frac{(x-\bar x)} {\bar x }$ where $\bar x$ is the mean ...
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1answer
36 views

Choosing right cut-off frequency for a LP filter in upsampler

I'm implementing a upsample function in Matlab but it's not perfect right now,for reasons I'm not sure. Here is my code: ...
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33 views

lock in detection based denoising using matlab?

What are the limitations of implementing the lock in detection technique in matlab? I have time varying data with known frequency with huge background noise. The reference signal is also available. ...
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39 views

Digital Tanlock carrier recovery loop

I’m currently trying to understand a digital tanlock carrier recovery loop for QPSK (for example) I cannot understand how it works. For example we an ideal QPSK constellation. phi = atan2(Q/I) = pi/...
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Reconstract the image from the modulus of its Fourier transform

In Reference, it is shown than one can recover the image by using only the modulus of its Fourier transform. It provides two iterative algorithm which is really similar to Gerchberg–Saxton method. ...
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How to find the time of beginning of the slope of the signal?

I have a time signal in MATLAB format. Sampling rate is 100k, so it is roughly 5 seconds of signal. See the link below https://www.dropbox.com/sh/v7vev2j14i77mlk/AAA-X7JGMAzO6IyElYmFPFwra?dl=0 If ...
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1answer
97 views

How determine the delay in my signal practically

I am trying to practically determine filter group delay so that I can try to reduce or adjust for it. I have tried all kinds of methods but still can't get the right result. I know that theoretically ...
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36 views

should implementing the MMSE equalizer in time domain and frequency domain give same results?

Assume we have a received signal $r$ explained as below: $r = h * x + n$ where $h, x ,*, n$ denote to the multi-path channel, transmitted signal, convolution operation and AWGN, respectively. ...
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1answer
29 views

Demodulating an oversampled OFDM signal

I'm trying to simulate an OFDM signal that has been captured with a receiver that has a much larger bandwidth than the OFDM signal. I tried the following MATLAB code to simulate an OFDM signal that's ...
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1answer
34 views

How to perform dechirping of SAR image in MATLAB?

I have the transmitted pulse and the raw SAR image before range compression (dechirping). I understand the pulse compression its a convolution along the columns but I am not able to make it work. I've ...
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1answer
58 views

Synthetic Aperture Radar (SAR). How to do Range Compression?

I am trying to perform range compression to a raw SAR image [fast times, sensor position], Dr in code. I have the transmitted signal (chirp), g in code, and literature says range compression is ...
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Applying Wavelet on energy disaggregation as denoising technique to remove uncertainties

I would like to apply Wavelet in MATLAB as a denoising technique on Non-Intrusive load Monitoring data. The data was captured by sensors on each appliance and one sensor on the smart meter (Normally ...
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How to generate rayleigh fading coefficients in matlab

I want to calculate received SNR for each cellular user CUs, so i want the corresponding transmission power P of base station BS to each user, the noise, and the channel gain coefficient of the ...
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1answer
42 views

Strange Response of a fir1 Filter in Matlab

i have been tinkering with some fir filters to bandpass-filter a signal. Even though the filter looks pretty descent in frequency domain, i receive a quite strange "filtered" signal in time-domain. I ...
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1answer
26 views

Image compression

What happens when an image is compressed by thresholding (choosing a suitable threshold and setting the values below the threshold to zero)? Setting the values to zero doesn't mean removing them. They ...
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1answer
35 views

GPS Receiver in Frequency Domain

I'm trying to transmit and receiver the GPS payload in both Time and Frequency Domain. For transmitting and receiving in time domain : ...
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1answer
34 views

How to Emulate Sample Frequency Offset for OFDM in Matlab?

I am studying the effect of sampling frequency offset on OFDM, and in order to emulate SFO, I have to slightly change the sampling rate of the signal. In order to have a +5ppm offset, I have to change ...
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1answer
62 views

What is the difference between (Sample Timing Offset), (Carrier Frequency offset), and (Sampling Frequency Offset)?

Briefly, can anyone explain to me what is the difference between (Sample Timing Offset), (Carrier Frequency offset), and (Sampling Frequency Offset)? and is Sampling Frequency Offset (SFO) like STO ...
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1answer
48 views

How do I find transfer functions from a state space representation?

Suppose I have a MIMO system in state space representation, for example: $A=\begin{bmatrix} 1 &2 &3 \\ 4&5 &6 \\ 7&8 &9 \end{bmatrix}$ $B=\begin{bmatrix} 2 &3 \\ ...
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1answer
39 views

Adding White Gaussian noise to a voice signal

I'm trying to add White Gaussian Noise to an audio file. However; the energy of the noise should be 1/10th of that of the signal. My first attempt is as following: ...
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35 views

How to plot histogram of difference of two images using MATLAB

i would like to calculate difference of two images. Then, histogram of difference of two images. So I can plot a histogram but I am not sure whether it is true or not? Also, I am not sure about what ...
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1answer
29 views

Implementing the noisy AR(1) Process

I'm trying to implement noisy AR(1) process and plot it. The observed noisy sequence x(n) = s(n) + w(n) where variance of w(n) = 0.2. s(n) is defined as an AR(1) process with s(n) = 0.5 s(n-1) + e(n)...
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1answer
169 views

Relationship between wavelet shape and wavelet filters

MATLAB has a library of wavelet functions, showing their "continuous forms" as well as the the decomposition and reconstruction filters. In decimated wavelet transform the filter size remains the ...
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1answer
29 views

Autocorrelation Computation with MATLAB

I have done the computation of the autocorrelation of a sequence (vector), here called "frame", and I have plotted it. Here the code: The resulting graph is: I do not understand the position of the ...
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2answers
47 views

Image resizing and interpolation

In digital image processing, I need to understand what does image resizing do? Does it only change the dimensions of the image, for example, from 256×256 to 128×128 with the same pixel spacing (the ...
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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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1answer
54 views

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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1answer
25 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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