FFT Analyzer Basic FAQ

An anti-aliasing filter is a low-pass filter used to prevent aliasing errors that can occur during sampling. Normally, the highest frequency (f m) contained in the input signal is unknown, so when performing frequency analysis with an FFT analyzer, the sampling frequency f s is determined, the power in the frequency band above 1/2 f s is sufficiently attenuated with the aforementioned low-pass filter, and then sampling is performed. This frequency of 1/2 f s is called the Nyquist frequency.

	3.5 Sampling Theorem (Regarding FFT Analyzers)