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Altera_Forum

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05-25-2010
01:41 PM

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frequency spectrum

Hallo,

I worked with the Altera FFT Megafunction.At the output i have an imaginery and a real part. but the output (sourcereal and sourceim)in the simulator is time-dependent. How can i get the frequency-spectrum for the signal? and how can i analyse the output, if its right or wrong?Link Copied

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Altera_Forum

Honored Contributor I

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05-25-2010
03:11 PM

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The I/Q of fft is the frequency domain.

so just plot the absolute value of output. IQ = I + jQ; power = 20* log10(abs(IQ)); %dB f = linspace(-.5*Fs,.5*Fs,fft_points) % if centered on dc else %f = linspace(0,1*Fs,fft_points); %Fs = fft clock frequency plot(f,power)
Altera_Forum

Honored Contributor I

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05-27-2010
09:53 AM

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