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sickness
New to the neighborhood
sickness
3 Posts
4 Jan 2007, 9:50am

MATLAB Help Needed - Noise and PSD

hi all,

I 've trying to solve this question since I 've taken it 20 days ago. The output is ZERO. I need help regarding this, pls help me solving or solve this question coz it is due soon and I got no thing to submit. I 've done my best but unfortunately, i got no thing.....

anyways, the questions is:

(a) i want to make a program that generate a random waveform with a gaussian pdf of zero mean and 2 Volts rms. Use vector of length 2048 and let the voltage values in the vector represent samples taken at 1millisecond intervels, so that the total duration of the signal is 2048 millisecound.

(b) plot the results waveform

(c)calculate the mean-square value of the wave form

(d)generate and plot the pdf to for the waveform and compare it to a true Gaussian by suprimposing on the same plot the PDF of the true Gussian

(e)calculate and plot the power spectral density (PSD) of the wave form use the Matlab psd command and normalise the results by dividing by the number of elements in your fft

(f)use the PSD to calculate the mean-square value of the original waveform

(g)calculate and plot the autocorrelation function for the waveform

(h)use the ACF the mean-square value of the original waveform

Can any one help me in this pls....

Thank you
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Kyle
dormant icrontic veteran
Kyle
98 Posts
4 Jan 2007, 3:35pm

Re: MATLAP help needed ASAP

LOL I just got my degree in Electrical Engineering and I can't help you with this at all. That's kinda sad. What class is this for? Do you have a book for the class? Is your problem that you don't understand the material or you don't understand MATLAB?

Good luck on finishing it in time
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shwaip
elaborate bot
shwaip
5,729 Posts
4 Jan 2007, 5:39pm

Re: MATLAP help needed ASAP

where's your code?
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sickness
New to the neighborhood
sickness
3 Posts
4 Jan 2007, 10:13pm

Re: MATLAP help needed ASAP

The course is Noise processing..
the material is easy to understand but there was no matlap work involved through the semster, this is just like a course project.. the code for part (a,b) and (c) is:

Part (a+b)

function y =sqrt(V)*randn(1,2048)+2 ;
y= 2*randn(1,n);
plot (y);
xlabel= sample index
ylabel= random number value
…………………………….
Part (c)
%msv=mean squar value
msn=0;
for i=1:n;
msv = msv+(2*randn)^2;
end
msv = msv/2048
end
.........................

this is the best i can do. Any help pls!!!

Thank you.
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Kyle
dormant icrontic veteran
Kyle
98 Posts
5 Jan 2007, 12:44am

Re: MATLAP help needed ASAP

You can plot data in MATLAB using the "plot" command. For more info on plot and other commands, type "help plot" in the MATLAB command prompt.

I could possibly help you translate your answers into MATLAB code (or plots) if you post your work/solutions.
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sickness
New to the neighborhood
sickness
3 Posts
5 Jan 2007, 5:18am

Re: MATLAP help needed ASAP

thank you guys for your help. But I didn't go any further than what i posted earlier. that's all what i got (till part c). Now I need to solve the rest... any ideas ???

thanks a gain
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shwaip
elaborate bot
shwaip
5,729 Posts
5 Jan 2007, 6:57am

Re: MATLAP help needed ASAP

does your code so far work?

there's a pdf() function, a corr() function (for finding autocorrellation). You can fft() the autocorrelation to get PSD, or you can use the psd() function.
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asdfgh
New to the neighborhood
asdfgh
1 Posts
14 Dec 2007, 7:54pm
hi sickness
Could you please e-mail me your matlab codes if you have found the answer.
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shwaip
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shwaip
5,729 Posts
17 Dec 2007, 8:07pm
It's unlikely that he (or you, I suppose) will ever read this post again. If you have a question, feel free to make a new post.
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