National Instruments NI 9229E - Manual (Page 10)

NI 9229E/9239E 10 ni.com
Stopband
The filter significantly attenuates all signals above the stopband
frequency. The primary goal of the filter is to prevent aliasing.
Therefore, the stopband frequency scales precisely with the data
rate. The stopband rejection is the minimum amount of attenuation
applied by the filter to all signals with frequencies within the
stopband.
Alias-Free Bandwidth
Any signal that appears in the alias-free bandwidth of the
NI 9229E/9239E is not an aliased artifact of signals at a higher
frequency. The alias-free bandwidth is defined by the ability of the
filter to reject frequencies above the stopband frequency and equals
the data rate minus the stopband frequency.
Understanding NI 9229E/9239E Data Rates
The frequency of a master timebase ( f
M
) controls the data rate ( f
s
)
of the NI 9229E/9239E. The NI 9229E/9239E includes an internal
master timebase with a frequency of 12.8 MHz, but the module
also can accept an external master timebase or export its
own master timebase. To synchronize the data rate of an
NI 9229E/9239E with other modules that use master timebases