Table des Matières
Publicité
®
R&S
RT-ZD40
5.2.1
Signal Loading for Differential Input Signals
The
figure 5-1
presents an equivalent circuit model of an R&S RT-ZD40 differen-
tial probe. The differential input impedance of the probe is equal to the impedance
between its positive (+) and the negative (-) signal socket. The resulting input
impedance versus frequency is indicated in
Fig. 5-6: Magnitude of the differential input impedance of the R&S RT-ZD40 probe as a
function of frequency
The differential input impedance varies greatly versus the frequency and is
defined by the following values:
● Differential input resistance R
● Differential input capacitance C
● Differential RF resistance R
5.2.1.1
Input Resistance R
The input resistance determines the loading of the DUT at DC and very low fre-
quencies (< 100 kHz). A low input resistance can potentially disturb measure-
ments of high-frequency signals as it influences the DC operating point of active
components.This effect is negligible for the majority of applications involving the
R&S RT-ZD40 probe due to the very high input resistance of the probe (1 MΩ).
User Manual 1410.5363.02 ─ 03
figure
= 2 R
dm
1
= C
+ C
dm
1
2
= 2 R
RF
2
dm
Measurement Principles
Signal Loading of the Input Signal
5-6.
/ 2
40
Publicité
Table des Matières
