how to write a programe in MATLAB to generate clean signal.

[dmiriy10]

matlab generate signal

Hi Dear, can any one explain me, how to write a programe in MATLAB to generate clean signal and adding noise to it ....... especially for bearings.....

Thanks

 

[konarkk]

program e^x in matlab

Hey .... Elaborate ur Query........... Wat type of clean signal You require...

Is it u require discrete Sin, Cos , exponenetal, simple pulse strain.......

below is a command for generating x[n] = [1 0 1 3 1]
where n = -2 to +2

----------------------- Matlab Command------

n=-2:1:2;
x=[1 0 1 3 1];
% To plot the data

stem(n,x);

Now to Add Noise....... Which type of Noise U require that u have to decide first....
Whether its White Gaussian Noise , Rayleigh Noise , .........

depending upon requirement there are inbuilt functions to generate pdf of noise.... gauss , rayleigh ... ricean... etc

Then Convolute obtained PDF with ur Message signal........ to obtain a signal containig noise..........

 

[Aya2002]

generate signal in matlab

Matlab Help:

The example generates a random digital signal, modulates it, and adds noise. Then it creates a scatter plot, demodulates the noisy signal, and computes the symbol error rate. For a more elaborate example that is similar to this one, see Modulating a Random Signal.

% Create a random digital message
M = 16; % Alphabet size
x = randint(5000,1,M);

% Use 16-QAM modulation to produce y.
y=modulate(modem.qammod(M),x);

% Transmit signal through an AWGN channel.
ynoisy = awgn(y,15,'measured');

% Create scatter plot from noisy data.
scatterplot(ynoisy);

% Demodulate ynoisy to recover the message.
z=demodulate(modem.qamdemod(M),ynoisy);

% Check symbol error rate.
[num,rt]= symerr(x,z)

The output and scatter plot follow. Your numerical results and plot might vary, because the example uses random numbers.

num =

83


rt =

0.0166

The scatter plot does not look exactly like a signal constellation. Where the signal constellation has 16 precisely located points, the noise causes the scatter plot to have a small cluster of points approximately where each constellation point would be.

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Added after 2 minutes:

by the way, I am agree with konarkk