Data Translation DT9820 Series, User Manual

Page: 25 / 112

Principles of Operation
13
2
2
2
2
2
2
2
2
2
According to sampling theory (Nyquist Theorem), specify a
frequency that is at least twice as fast as the input’s highest frequency
component. For example, to accurately sample a 20 Hz signal, specify
a sampling frequency of at least 40 Hz. Doing so avoids an error
condition called aliasing, in which high frequency input components
erroneously appear as lower frequencies after sampling.
50 Hz 800 Samples/s 16.5
400 Samples/s 17.0
200 Samples/s 17.5
100 Samples/s 20.9
50 Samples/s 21.4
25 Samples/s 21.9
12.5 Samples/s 22.4
6.25 Samples/s 22.9
Table 3: Sampling Rate (cont.)
Operating Mode Sampling Rate Effective Number of Bits