Characteristics of Differential Probes
R&S
®
RT-ZD40
27
User Manual 1410.5363.02 ─ 05
4
Characteristics of Differential Probes
A differential probe has three sockets: the positive signal socket (+), the negative
signal socket (-), and the ground socket.
Figure 4-1: Input voltages on a differential probe
Multiple input voltages can be defined for a differential probe:
●
Differential mode input voltage (V
in
, V
dm
)
Voltage between the positive and negative signal sockets
●
Positive single-ended input voltage (V
p
)
Voltage between the positive signal socket and the ground socket
●
Negative single-ended input voltage (V
n
)
Voltage between the negative signal socket and the ground socket
●
Common mode input voltage (V
cm
)
Mean voltage of positive and negative signal sockets referred to the ground
socket, respectively
Two of these voltages are independent values, the other two can be calculated:
2
n
p
cm
n
p
in
V
V
V
V
V
V
Typically, the differential and the common mode input voltages are used to
describe the behavior of a differential probe.
