4-14
Cabling and Wiring
As discussed in “Understanding the DAS-TC/B Inputs” on page 4-8, the
common mode connection is provided by the internal 10k
Ω
resistor.
Alternatively, a floating signal source can be connected as in Figure 4-10.
Figure 4-10. Connecting a Floating Signal Source, Method 2
However, this approach is usually less desirable. Jumpering the analog
ground (B GND) to the Low input effectively changes the differential
input into a single-ended input. If noise picked up electrostatically by the
positive and negative leads is similar—and therefore much of the noise is
essentially a common mode component, this unbalanced configuration
inhibits the ability of the input amplifier to reject the noise.
Connecting a Grounded Signal Source
If any of your signal sources are coupled to ground, connect them as
shown in Figure 4-11.
Channel n High
Channel n Low
Optional Shield
Es
STA-TC/B
or
STP-TC/B
Chassis
GND
Input
Amplifier
(To chassis via
S-1800 cable
for STA-TC/B)
B GND
Es
Signal
Source
+
-
Jumper
