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help TT : continuous time signal to frequency domain using matlab fft

Dear all,

 

I am a newbie to labview software. Please forgive me to ask such question as I just learnt how to use it few weeks ago. Basically I am trying to use the software to acquire complex values from my sensors. My experimental setup consists of two speakers which generate sinusoidal sound waves and four pressure transducers which are used to acquire the complex pressure readings. I know in order to get complex readings, the only way (or are there other ways) is to convert the continuos time signals to frequency domain using fft. Attached are the block diagrams of my system.

 

My fft code for one sensor :

 

nfft = 2^nextpow2(N);

P1=fft(p1,nfft);
P1=P1(1:nfft/2);
P1_real=real(P1);
P1_im=imag(P1);

 

However the indicator shows only the pressure magnitude.
The imiginary part of the result is always zero.


Thanks in advance for answering my question.

 

Best regards,

dave

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The FFT Spectrum (Real-Im) would seem more appropriate than you making up your own.

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