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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24 views

Missing some Matlab functions in Octave

I need following functions which is not in Octave : paddedsize(); dftuv(); I already installed this packages on Octave : ...
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1answer
29 views

How to get spectrum of an image?

I have an image : img = imread('pic.jpg'); Now, How can I get spectrum of that image?
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1answer
34 views

Why dont sin and phase shifted cosine overlap?

I plotted a sine wave(blue) and a 90 degrees phase shifted cosine wave (red) expecting them to overlap each other. ...
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1answer
18 views

How to read an image in Scilab

In Matlab we use below function to read an image : var = imread('IMAGE‌‌ ‌PATH'); But, how to do same thing in Scilab ?
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20 views

How to understand energy function in thin plate splines?

guys! I have carried out some experiments using matlab warp tools from here. But the results are not good, so I decide to read its original paper Principal Warps: Thin-Plate Splines and the ...
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0answers
12 views

Image to Binary stream for OFDM with qpsk/qam modulation matlab

Im looking to covert a .png or .jpeg image into bitstream so that I can further use it as input bit stream for OFDM with QPSK/QAM modulation in Matlab. I would really appreciate the help on that. ...
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1answer
21 views

Differences between matlab's 'impulse' and 'lsim' command; create impulse response

I've got following problem: assume you've this continous system 1st order: $$ H(s) = \frac{1}{1+s} $$ s = tf('s'); sys = 1/(1+s); I'm going to discretize this ...
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2answers
61 views

How to calculate the local gradient of an image in MATLAB

I know that the gradient function is supported by matlab, but the local gradient is not, so how do you calculate it?
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2answers
26 views

Using Matlab xcorr to find a signal hidden behind noise

I am trying to develop some code to find a transient signal in a data set I have. Before I get there however I am trying to write code using simulated data. I first am creating a signal with a ...
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25 views

Which method overcome false edge problem [on hold]

I have one problem that is false edge problem. Given a image with real edge and false edge. How to detect where is real edge? Which method?
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0answers
23 views

Amplitude and frequency plot for an input image.

This is my original image: First I have plotted scale vs frequency then transformed scale to frequency and got frequency-time plot: I have plotted highest power of coefficients (indicated by ...
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2answers
32 views

separate signal values from noise

let us consider following graph of singular values i want to make some kind of clustering of these data,namely to seperate main components from non main components,let say signal components ...
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2answers
37 views

will always periodogram produce correct frequencies?

let say we have some data,some signal written in this form $x(t)=s(t)+\epsilon(t)$ where $s(t)$ is pure signal and $\epsilon(t)$ is white noise with mean zero and some variance ,question is ...
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0answers
23 views

How to use pseudo frequencies with wavelet transforms

I'm slowly getting my head around the use of wavelet transforms (CWT & DWT) with my data, but I'm interested in how the wavelet transforms correspond to certain bands of frequencies. I'm using ...
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13 views

Algorithm Switch in Simulink

I am currently working on a control mechanism which looks as in the following figure: In general, I'd like the input1 (the one where only gain and integrator are present), if and only when input2 ...
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1answer
40 views

reconstruction of time series in SSA

i am trying to reconstruct time series from SSA ,because according to this link http://en.wikipedia.org/wiki/Singular_spectrum_analysis there is procedure ...
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0answers
30 views

Matlab : Reconstructing signal from cosinusoïdes : DC offset question [code + picture]

i'm trying to reconstruct a signal from amplitude and phase of cosinusoides to understand totally how DCT works. So far i've managed to get the signal very close, only by a DC offset that i don't get. ...
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1answer
42 views

EEG signal processing

I have an EEG data set downloaded from physionet. I want to play that data into a brain monitoring device like for example BIS monitor or Narcotrend or any other similar brain monitoring device.I use ...
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1answer
46 views

matlab's FFT is wrong? don't think so

i'm trying to get an FFT of a signal my FFT has 1024 samples i added two sin functions one of freq 86,13Hz (2*44100/1024) and one of freq 129,19Hz (3*44100/1024) the WAV looks like that (for 1 ...
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1answer
36 views

Log energy calculation

I have some code here that I don't quite understand. It calculates the energy for a given frame the following way: En=log(1+energy(32767*frame)) The energy ...
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1answer
57 views

use wavelet for improving spectral resolution

let us consider following code ...
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0answers
46 views

CWT for filtering / feature extraction

I had asked a question last night in regards to how to process my data (Noise rejection / feature extraction) but I have a more specific question now that I hope someone can answer. As mentioned in ...
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21 views

error calculation and ber

I have this NRZ-L model: where the subsystem contains the following: . What is exactly the operation of this error calculation subsystem?
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42 views

Signal-to-Quantization Noise ratio

What is the formula of the signal-to-Quantization Noise ratio for a quantizer as shown in the figure below (input being the top and output being the bottom figure) Do different quantizer types have ...
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1answer
78 views

Calculation of cosine in frequency domain instead of calculatin in time-domain followed by a FFT

I got an $N$, in my case 512, point FFT of a real-valued signal. Based on some calculation in my application I determine the parameters $k \in [1, N-1]$, the number of oscillations per period, $\phi ...
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0answers
42 views

The order analysis in MATLAB [duplicate]

Can anybody tell me how to calculate the order analysis / spectrum of a signal? I've been searching in vain. I want to use MATLAB to analyse the signal / sound of a motor. For more information about ...
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1answer
64 views

How to analyse the sound of Motor

I have a motor, that I want to analyse, using its sound, so I can its 'character' I was using the the simple fft, and figured out, that it wouldn't help, so I tried the order analysis, at least I ...
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0answers
23 views

Matlab:Sampling Curve into Frames and Plotting

I have a Output Curve of following characteristics http://i.imgur.com/hABfsiC.jpg Following is the data which represents the output curve cited above ...
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0answers
10 views

Help in simulink for detecting specific parts of the signals

I am modeling some real-time ECG signals in simulink, and as I detect the zero-crossings or the peak of the pulse for this signal, I want to display the samples at which this occurs in the scope. This ...
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36 views

IIR filter SOS and Direct Forms doubt

I have below doubts, so confusing! As I don't want to assume from what I read, I am asking for help here! Are Second Order Sections another name for biQuads ? If I have 2 single pole transfer ...
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1answer
56 views

Time duration of a signal to determine the peak frequency

I have two questions regarding signal processing: 1) In my analysis I generate a signal in the time domain with a frequency of 0.1 Hz. I apply the FFT and then determine the peak frequency of the ...
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1answer
59 views

use prony method for damped exponentials

let us consider represented of damping exponential model by prony method,there is source code ...
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2answers
74 views

generating pilot sub-carriers in matlab

I wanted to simulate OFDM system in MATLAB. I'm using Fixed WiMAX OFDM parameters in my simulation, where the number of data sub-carriers are 192, number of Pilot sub-carriers are 8, number Null ...
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11 views

how to chose independent sample from a non linear regression problem

I would have a question concerning the first part of my assignment here below: (in bold) In this problem, the objective is to approximate a nonlinear function using a feedforward artificial neural ...
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1answer
45 views

Polyphase decimation matlab

I am new to DSP, and currently trying to implement a simple polyphase decimation program in matlab. M is decimation factor, x is input (for now it is a square wave 8096 samples), y_polyDec is result ...
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1answer
67 views

Problem with Kalman filtering accelerometer data

I'm having some trouble implementing a Kalman filter in MATLAB. I have an Android phone connected sending data from accelerometer for 10 seconds. After i have the data I take out the x-axis vector. ...
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20 views

Hough Transform - sign of rho and theta- Matlab

I understood that origin of the picture space (x,y) will be upper left corner. Origin of the parameter space (rho, theta) will be center point. I understood basic idea of the hough transform. I am ...
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1answer
43 views

snr relation with modulation index and noise power

What is the relation between the AM modulation index and the SNR?(I plotted this and it came as the shape of the exponential graph) Also what is the relation between the channel noise power and the ...
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2answers
42 views

1.0e-03 * 0.9734 numerical representation in Matlab [duplicate]

Is 1.0e-03 * 0.9734 equivalent to 0.9734 * 10^-3 = 0.0009734 ? Because I am not sure
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49 views
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62 views

Design Filter Banks for every 100 Hz

I need to study a wave file for every 100 Hz. However, I dont know how can I design filer for each 100 Hz. Let's say 0-100 Hz, 100-200 Hz, ... , ((fs/2)-100) _ (fs/2) Hz. Is it any MATLAB code for ...
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2answers
57 views

2D Deconvolution in matlab

I am trying to solve the following equation for h (an [MxM matrix]): $$ k[\tau_1,\tau_2]=\sum_{i_1=0}^M \sum_{i_2=0}^M h[i_1,i_2]x[\tau_1-i_1]x[\tau_2-i_2] $$ I have k, which is a 2D [MxM] symmetric ...
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1answer
57 views

ARMA models for non stationary signals

let us suppose that we have non stationary signal,whose value is given by ...
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1answer
36 views

999e3 numerical representation in Matlab [closed]

Is 999e3 in matlab = 0.999? Because I am not sure whether e mean exponential or you move the decimal point by 3decimal places
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1answer
45 views

Simulink for Amplitude Modulation

I am using Matlab Simulink to analyse Amplitude Modulation in Noise. I attached my system below. My problems: 1)In the mixer I am using a bandpass filter and another one after the envelope ...
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0answers
20 views

get similar picture from wavelet transform

my today's question is related to previous question about wavelet, ...
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1answer
46 views

use chirp z transform for spectral resolution

let us suppose that we some signal $x(t)$,which consist of sinusoidal components and white noise,i would like to know how to use chirp z transform for improving spectral resolution?i found this ...
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3answers
74 views

What is benefit when convert signed 16 bit to unsigned 8 bit in medical image?

I have an image with its type is 16 bit signed. I see some paper, the author often convert it to unsigned 8 bit. But they did not explain why they do it. Could you explain what is benefit of this ...
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0answers
37 views

How to Prevent overflow/saturation in fixed point implementation of Fast Data Projection Algorithm

I am trying to implement an algorithm in real-time on a Fixed point DSP (The Blackfin from Analog Devices). The algorithm does a lot of stuff, but in the middle it performs an algorithm called "Fast ...
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1answer
28 views

Convert normalized frequency to real frequency in AR model

Let us suppose that we have modeled signal using AR model, and suppose we have following model: I used spectral estimation function from MATLAB pyulear Now ...