Data Translation DT9820 Series, User Manual

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Chapter 2
12
A/D Sample Clock
If you specified channel 0 in a channel list and specified the gain in a
gain list, you can clock the A/D conversions using an internal A/D
sample clock on the DT9820 Series function module.
The internal A/D sample clock uses a 4.9152 MHz time base for
60 Hz operations or a 4.0960 MHz time base for 50 Hz operations.
You specify whether you want to use 60 Hz or 50 Hz operations using
the Control Panel; refer to the DT9820 Series Getting Started Manual for
information on how to configure the driver.
Using software, specify the clock source as internal and the clock
frequency at which to pace the operation.
Table 3 lists the supported
frequencies and the effective number of bits at each frequency.
Table 3: Sampling Rate
Operating Mode Sampling Rate Effective Number of Bits
60 Hz 960 Samples/s 16.5
480 Samples/s 17.0
240 Samples/s 17.5
120 Samples/s 20.9
60 Samples/s 21.4
30 Samples/s 21.9
15 Samples/s 22.4
7.5 Samples/s 22.9