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NI USB-9237 User Guide and Specifications 16 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 that would be aliased into the alias-free bandwidth.
Alias-Free Bandwidth
Any signal that appears in the alias-free bandwidth of the NI USB-9237
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.
Specifications
The following specifications are typical for the range 0 to 60 °C unless
otherwise noted.
Input Characteristics
Number of channels................................4
Bridge completion
Full and half.....................................Internal
Quarter.............................................External
ADC resolution.......................................24 bits
Type of ADC ..........................................Delta-sigma (with analog
prefiltering)
Sampling mode .......................................Simultaneous
Data rates (f
s
) ......................................... , n = 1, 2, ... 31
Master timebase (internal)
Frequency ........................................12.8 MHz
Accuracy..........................................± 100 ppm max
Nominal full-scale range ........................± 25 mV/V
Scaling coefficient ..................................2.9802 nV/V per LSB
5
0.000 kS/
s
n
-
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