Nyquist frequency [SEP] named after
Nyquist frequency
The Nyquist frequency, named after electronic engineer Harry Nyquist, is half of the sampling rate of a discrete signal processing system. It is sometimes known as the folding frequency of a sampling system.  An example of folding is depicted in Figure 1, where f is the sampling rate and 0.5 f is the corresponding Nyquist frequency.  The black dot plotted at 0.6 f represents the amplitude and frequency of a sinusoidal function whose frequency is 60% of the sample-rate (f). The
frequency components of the VF signal, a filter named a Nyquist filter is used in receivers. This filter, which is used before demodulation, is actually a low-pass filter with 6 dB suppression at the intermediate frequency (IF) carrier. Thus the level of double sideband portion of the VF signal is suppressed and the original band characteristic is reconstructed at the output of the demodulator.
The tolerance masks of the Nyquist filter.
The specifications below are given for sound trap off case. System B (G or