Comparing Welch and FFT power spectrum density

1. What is the difference between power spectral density and FFT?
2. What is the difference between power spectrum and power spectral density?
3. What is Welch power spectral density?
4. Is power spectral density a FFT?

What is the difference between power spectral density and 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 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.

What is Welch power spectral density?

Welch, is an approach for spectral density estimation. It is used in physics, engineering, and applied mathematics for estimating the power of a signal at different frequencies.

Is power spectral density a FFT?

The Power Spectral Density is also derived from the FFT auto-spectrum, but it is scaled to correctly display the density of noise power (level squared in the signal), equivalent to the noise power at each frequency measured with a filter exactly 1 Hz wide.