Solving FFT Signal Processing Problem for Complex Time Signal

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SUMMARY

The discussion focuses on solving an FFT signal processing problem for a complex time signal defined as x(t)=X1*exp(i*∅)+X2*exp(i*2*∅). The user successfully obtains the frequency components at ω and 2ω but struggles with retrieving the correct amplitudes X1 and X2 due to phase differences. It is established that if the FFT is performed correctly, the amplitudes should be recoverable. The user is prompted to consider the sampling rate and the number of samples in relation to the frequency ω.

PREREQUISITES
  • Understanding of FFT (Fast Fourier Transform) algorithms
  • Knowledge of complex exponential functions in signal processing
  • Familiarity with frequency domain analysis
  • Experience with sampling theory and Nyquist criteria
NEXT STEPS
  • Investigate the impact of sampling rate on FFT results
  • Learn about windowing techniques to improve amplitude accuracy in FFT
  • Explore methods for phase unwrapping in signal processing
  • Study the effects of aliasing and how to prevent it in FFT analysis
USEFUL FOR

Signal processing engineers, researchers in communications, and anyone involved in analyzing complex time signals using FFT techniques.

shravz
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Hi, I have a complex time signal x(t)=X1*exp(i*∅)+X2*exp(i*2*∅). On converting to frequency domain, i expect frequency components at ω and twice of ω (when ∅=ω*t). FFT gives the desired frequencies, but the amplitudes don't correspond to X1 and X2. I understand that this is due to the phase difference between the signals X1*exp(i*∅1) and X2*exp(i*2*∅). My question is how should i get back the amplitudes X1,X2,... when multiple frequency components exist in the signal.

P.S: when only x(t)=X1*exp(i*∅1);am able to get back X1 in the fft.

Thanks in advance.
 
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It is not a question of phase. If you did everything correctly, you should get X1 and X2 back.

What is the sampling rate and number of samples compared to w?
 

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