Analog Input Lowpass Filter - National Instruments M Series User Manual

Table 4-1 shows the input ranges and resolutions supported by each M Series device family.
Table 4-1. M Series Input Range and Nominal Resolution
M Series Devices
NI 622x
NI 625x
NI 628x

Analog Input Lowpass Filter

A lowpass filter attenuates signals with frequencies above the cutoff frequency while passing,
with minimal attenuation, signals below the cutoff frequency. The cutoff frequency is defined as
the frequency at which the output amplitude has decreased by 3 dB. Lowpass filters attenuate
noise and reduce aliasing of signals beyond the Nyquist frequency. For example, if the signal of
interest does not have frequency components beyond 40 kHz, then using a filter with a cutoff
frequency at 40 kHz attenuates noise beyond the cutoff that is not of interest. The cutoff
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Nominal Resolution Assuming
Input Range
-10 V to 10 V
-5 V to 5 V
-1 V to 1 V
-200 mV to 200 mV
-10 V to 10 V
-5 V to 5 V
-2 V to 2 V
-1 V to 1 V
-500 mV to 500 mV
-200 mV to 200 mV
-100 mV to 100 mV
-10 V to 10 V
-5 V to 5 V
-2 V to 2 V
-1 V to 1 V
-500 mV to 500 mV
-200 mV to 200 mV
-100 mV to 100 mV
M Series User Manual
5% Over Range
320 µV
160 µV
32 µV
6.4 µV
320 µV
160 µV
64 µV
32 µV
16 µV
6.4 µV
3.2 µV
80.1 µV
40.1 µV
16.0 µV
8.01 µV
4.01 µV
1.60 µV
0.80 µV
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