NI 9233 Operating Instructions and Specifications
14
ni.com
Stopband
The filter significantly atten
u
ates all signals above the stopband
freq
u
ency. The primary goal of the filter is to prevent aliasing.
Therefore, the stopband freq
u
ency scales precisely with the data
rate. The stopband rejection is the minim
u
m amo
u
nt of atten
u
ation
applied by the filter to all signals with freq
u
encies within the
stopband.
Alias-Free Bandwidth
Any signal that appears in the alias-free bandwidth of the NI 9233
is not an aliased artifact of signals at a higher freq
u
ency. The
alias-free bandwidth is defined by the ability of the filter to reject
freq
u
encies above the stopband freq
u
ency and it is eq
u
al to the data
rate min
u
s the stopband freq
u
ency.
Understanding NI 9233 Data Rates
The freq
u
ency of a master timebase (
f
M
) controls the data rate (
f
s
)
of the NI 9233. The NI 9233 incl
u
des an internal master timebase
with a freq
u
ency of 12.8 MHz, b
u
t the mod
u
le also can accept an
external master timebase or export its own master timebase. To
synchronize the data rate of an NI 9233 with other mod
u
les that
u
se
master timebases to control sampling, all of the mod
u
les m
u
st
