© National Instruments Corp. 25 NI 9237 Operating Instructions and Specifications
Rejection at oversample rate1
fs = 10 kS/s..................................60 dB @ 640 kHz
fs = 50 kS/s..................................90 dB @ 3.2 MHz
Common-mode voltage,
all signals to earth ground.................±60 VDC
CMRR
Relative to earth ground2
(fin = 0 to 60 Hz).........................140 dB
Relative to EX–
(fin = 0 to 1 kHz)......................... 85 dB
SFDR (1 kHz, –60 dBFS).................106 dB
Total Harmonic Distortion (THD)
1 kHz, –20 dBFS........................100 dB
8 kHz, –20 dBFS........................ 90 dB
1 Rejection by analog prefilter of signal frequencies at oversample rate.
2 Measured with a balanced cable. Shielded cables that are not twisted-pair may be
significantly unbalanced. To improve the balance of shielded, twisted-pair cables,
NI recommends twisting together the AI+/AI– pair, the RS+/RS– pair, and the
EX+/EX– pair.