Question

What is Nyquist’s Bandwidth?

Answer 1

The Nyquist rate or frequency is the minimum rate at which a finite bandwidth signal needs to be sampled to retain all of the information. For a bandwidth of span B, the Nyquist frequency is just 2 B. If a time series is sampled at regular time intervals dt, then the Nyquist rate is just 1/(2 dt ).

The Nyquist formula gives the upper bound for the data rate of a transmission system by calculating the bit rate directly from the number of signal levels and the bandwidth of the system.

Specifically, in a noise-free channel, Nyquist tells us that we can transmit data at a rate of up to

C = 2B log2 M

bits per second, where B is the bandwidth (in Hz) and M is the number of signal levels.

Nyquist is only an upper bound, and on the baseband signal bandwidth - the occupied transmission bandwidth for a wireless signal will further depend on how the signal is modulated onto a carrier frequency for wireless transmission.