Transmission Line Effects - National Instruments NI 6608 User Manual

Transmission Line Effects

© National Instruments Corporation
Table 3-9. Signals and D GND Pin Number on 68-Pin Connector Block (Continued)
PFI Number
PFI 24
PFI 25
PFI 26
PFI 27
PFI 28
PFI 29
PFI 30
PFI 31
PFI 32
PFI 33
PFI 34
PFI 35
PFI 36
PFI 37
PFI 38
PFI 39
Transmission line effects can degrade the signal and cause measurement
errors. Use twisted-pair wires to connect external signals to the device to
improve impedance matching and signal integrity. The NI 660x provide
onboard series termination to reduce signal reflections when it drives an
output.
For reflection problems that occur when the device drives the signal,
use parallel AC termination at the destination. When using a National
Instruments SH68-68-D1 cable, the recommended values for R
68 W and 150 pF, respectively.
Pin Number for D GND
30
30
65
65
33
33
68
68
42
39
42
41
39
41
36
36
3-23
Chapter 3 Signal Connections
and C
P
NI 660x User Manual
are
P