HOW CAN I BROADEN MY SIN SIGNAL
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I need to plot a sin signal and analyse it using a spectrum analzer (periodogram) but i want to broaden the sin signal how is it possible??
3 个评论
Image Analyst
2012-4-1
Do you mean (1) you want to increase the period (wavelength) of a perfect sine wave? Or (2) are you looking at it's spectrum, which would be a delta function, and wanting to broaden it from a delta function into something wider, like a sinc function (which you'd get by multiplying your sine by a rectangular window in the spatial domain), indicating that there are more frequencies present now than just your original frequency of your original sine wave? Which case is it, #1 or #2?
raj
2012-4-1
raj
2012-4-1
采纳的回答
raj
2012-4-3
0 个投票
1 个评论
Walter Roberson
2012-4-3
chirp signals do not have flat-topped peaks.
Anyhow, you marked the question as Accepted, so you have come up with an answer suitable for your purpose, right?
更多回答（5 个）
Rick Rosson
2012-4-1
0 个投票
Multiply your sine wave by a narrow window function.
5 个评论
raj
2012-4-1
Walter Roberson
2012-4-2
You could give us a hint as to what you _are_ allowed to use.
raj
2012-4-2
Walter Roberson
2012-4-2
If that is your only requirement, then why are you not _allowed_ to multiply your sine wave by a narrow window function? What other restriction have been placed on the form of your solution?
raj
2012-4-2
Image Analyst
2012-4-2
0 个投票
How about using conv() to convolve your perfect sine signal with some crazy kernel?
Honglei Chen
2012-4-2
Are you just looking for a sin that does not fall on an exact frequency sampling point so on the graph it seems having some kind of leakage, like the code below does?
fs = 128;
N = 32;
f = 10;
t = (0:N-1)/fs;
x = sin(2*pi*f*t);
Nfft = 128;
plot((0:Nfft-1)/Nfft*fs,abs(fft(x,Nfft)))
This doesn't really broaden your sin signal though.
Rick Rosson
2012-4-2
0 个投票
Hi Raj,
We are not mind readers, and we are not really interested in pulling teeth to figure out what you need. Please tell us exactly what you are trying to do, why you want to do it a certain way, and what specific constraints or restrictions you are facing.
Also, if you have any MATLAB code that you have started developing, please post it and ask us specific questions related to your code.
Thanks!
Rick
1 个评论
Walter Roberson
2012-4-2
For example are you looking for the equivalent of a zero-order hold but applied in the frequency domain ?
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