Chapter3 DigitizerBasics
©NationalInstruments Corporation 3-3 NI5102 User Manual
Sample Rate
Sample rate is the rate at which a signal is sampled and digitized by an
ADC. According tothe Nyquist theorem, a higher sample rate produces
accuratemeasurement of higher frequency signals if the analog bandwidth
is wide enough to let the signal to pass through without attenuation.
A highersample rate also captures more waveform details.
Figure3-3illustratesa1MHzsinewavesampledbya2MS/sADCanda
20 MS/s ADC. The faster ADC digitizes 20 points per cycle of the input
signalcompared with 2 points per cycle with the slower ADC. In this
example,the higher sample rate more accurately captures the waveform
shape as well as frequency.
Figure3-3. 1MHz Sine Wave Sample
=Sample Rate 2 MS/s
=Sample Rate 20 MS/s