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PCIE-1816_1816H User Manual
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However, this connection has the disadvantage of loading the source down with the
series combination (sum) of the two resistors. For ra and rb, for example, if the input
impedance rs is 1k Ohm, and each of the two resistors is 100k Ohm, then the resis-
tors load down the signal source with 200 Ohm (100 Ohm+ 100 Ohm), resulting in a -
0.5% gain error. The following gives a simplified representation of the circuit and cal-
culating process.
AI Sample Clock Sources Connections
Internal AI Sample Clock
The internal AI sample clock uses a 100 MHz time base. Conversions start on the ris-
ing edge of the counter output. You can use software to specify the clock source as
internal and the sampling frequency to pace the operation. The minimum frequency
is 0.024 S/s, the maximum frequency is 500 KS/s. According to the sampling theory
(Nyquist Theorem), you must specify a frequency that is at least twice as fast as the
input’s highest frequency component to achieve a valid sampling. For example, to
accurately sample a 20 kHz signal, you have to specify a sampling frequency of at
least 40 kHz. This consideration can avoid an error condition often know as aliasing,
in which high frequency input components appear erroneously as lower frequencies
when sampling.
Summary of Contents for PCIE-1816
Page 1: ...User Manual PCIE 1816 1816H 16 bit Multi function Card with PCI Express Bus ...
Page 4: ...PCIE 1816_1816H User Manual iv ...
Page 10: ...PCIE 1816_1816H User Manual 4 Figure 1 1 Installation Flow Chart ...
Page 36: ...PCIE 1816_1816H User Manual 30 ...
Page 37: ...Appendix A A Specifications ...
Page 38: ...PCIE 1816_1816H User Manual 32 A 1 Function Block ...
Page 42: ...PCIE 1816_1816H User Manual 36 ...
Page 43: ...Appendix B B Operation Theory ...
Page 61: ...55 PCIE 1816_1816H User Manual Appendix B Operation Theory ...