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signal,complex signal,spectrum

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jagdeesh kumar

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Feb 28, 2011, 9:16:19 AM2/28/11
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dear sir ,

>>i am jagadeesh..
>> i am working on real signal ,complex signal .. and their corresponding spectrum >>through mat lab...

>>i am using the following signal
>>a=[-.0621 .0039 .4132 .5466 .1479 -.0670 .0010 .0165]

>>b=fliplr(a)
>>x=-3:1:4;
>>plot(x,a,'r')
>>hold on;
>>plot(x,b,'b')
>>hold off
>>axis([-3 4 -1.0 1.0 ])
>> t=a+(i*b);

>>here i need to get the spectrum of real signal
>> a and b

>>and then complex signal t....
>>how to get the spectrum of those signals....

>>the spectrum i needed is double sided... with reducing side lobes amplitudes (like >>sinc pulse) ...
>>i tried with fft .. but i am not getting double side spectrum.....


>>please if any known about the spectrum of signal , help me to get progress in >>my work...

>>thanks for Ur advance help.............

Greg Heath

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Mar 1, 2011, 10:21:05 AM3/1/11
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> >>thanks for Ur advance help.............- Hide quoted text -
>
> - Show quoted text -

help fftshift
doc fftshift


Hope this helps.

Greg

Wayne King

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Mar 1, 2011, 10:59:05 AM3/1/11
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"jagdeesh kumar" <jaga...@yahoo.co.in> wrote in message <ikganj$3tp$1...@fred.mathworks.com>...

Hi Jagdeesh, In addition to Greg's fine suggestion, if you have the Signal Processing Toolbox, you can use spectrum objects with 'SpectrumType' 'Twosided' with or without 'CenterDC' set to true.

x = randn(1e3,1)+1j*randn(1e3,1);
hper = spectrum.periodogram;
plot(psd(hper,x,'SpectrumType','twosided','CenterDC',true));
% to get the output
psdest = psd(hper,x,'SpectrumType','twosided','CenterDC',true);

Wayne

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