National Instruments NI 5102 用户手册
Chapter 3
Digitizer Basics
© National Instruments Corporation
3-3
Sample Rate
Sample rate is the rate at which a signal is sampled and digitized by an
ADC. According to the Nyquist theorem, a higher sample rate produces
accurate measurement of higher frequency signals if the analog bandwidth
is wide enough to let the signal to pass through without attenuation.
A higher sample rate also captures more waveform details.
ADC. According to the Nyquist theorem, a higher sample rate produces
accurate measurement of higher frequency signals if the analog bandwidth
is wide enough to let the signal to pass through without attenuation.
A higher sample rate also captures more waveform details.
Figure 3-3 illustrates a 1 MHz sine wave sampled by a 2 MS/s ADC and a
20 MS/s ADC. The faster ADC digitizes 20 points per cycle of the input
signal compared 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
20 MS/s ADC. The faster ADC digitizes 20 points per cycle of the input
signal compared 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
.
Figure 3-3. 1 MHz Sine Wave Sample
= Sample Rate 2 MS/s
= Sample Rate 20 MS/s