How does Power Spectrum remain symmetric in Z domain?

1. Why is the Fourier transform symmetric?
2. What is the difference between power spectrum and power spectral density?
3. Is power spectrum same as FFT?
4. What does power spectrum tell us?

Why is the Fourier transform symmetric?

Because both the positive and negative frequency sinusoids are 90 degrees out of phase and have the same magnitude, they will both respond to real signals in the same way.

What is the difference between power spectrum and power spectral density?

These two terms are used interchangeably throughout the signal processing and mathematics communities; at a conceptual level, there is no difference between these two terms. The two terms both describe how the intensity of a time-varying signal is distributed in the frequency domain.

Is power spectrum same as FFT?

The PSD and FFT are tools for measuring and analyzing a signal's frequency content. The FFT transfers time data to the frequency domain, which allows engineers to view changes in frequency values. The PSD takes another step and calculates the power, or strength, of the frequency content.

What does power spectrum tell us?

The power spectrum of a signal indicates the relative magnitudes of the frequency components that combine to make up the signal. The data used to determine the power spectrum must reflect sufficient excitation in the signal.