Bandwidth, Sample Rate, and Nyquist Theorem

The two major components in a high-speed digitizer's analog front end are the analog input path and the analog-to-digital converter (ADC). The analog input path attenuates, amplifies, filters, and/or couples the signal to optimize the digitization by the ADC. The ADC samples the conditioned waveform and converts the analog input signal to digital values that represent the conditioned input signal.

Bandwidth describes the analog front end's ability to get a signal from the outside world to the ADC with minimal amplitude loss. Sample rate is the frequency at which the ADC converts the analog input waveform to digital data. The Nyquist Theorem explains the relationship between the sample rate and the frequency of the measured signal. Each of these terms is discussed in more detail below.