Rohde & Schwarz SMBV100A, Руководство по эксплуатации

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Instrument Function
R&S
®
SMBV100A
229 Operating Manual 1176.8016.02 ─ 17
Example: How to set up a closed loop power control
Figure 5-11: Example of a test setup with NRP-Z Level Control
As shown in the example, the sensor measures a proportional power in defined time
intervals, derivated from a coupler. It considers optionally given S-parameters and
returns the results to the generator. The signal generator compares the measured level
with the set value and adjusts its output level accordingly.
This allows you to control the external signal level continuously and reliably reach a
constant input level at the DUT in real time.
Impact of the NRP-Z Level Control and the Operating Modes
Since the frequency and level of the RF output signal are continuously adjusted during
"NRP-Z Level Control", this operating mode interferes those with varying frequency
and level values.
The reason is, that the generator regularly transmits the output frequency to the con-
nected R&S NRP-Zxx power sensor, which in turn requests the signal generator to
adjust the output level according to its measurement. In contrast to this real time con-
trol loop, for example the list operating mode already generates the RF output signal
on previously optimized frequency and level value pairs. In this case, the "NRP-Z Level
Control" as a second control loop would impact the already determined RF signal val-
ues and also considerably slow down the measurement. Similar impacts occur in
sweep mode, and also the "NRP-Z Power Viewer" and "NRP-Z Level Control" affect
each other's functionality.
Hence, the operating modes exclude each other as follows:
●
"NRP-Z Level Control" automatically disables NRP-Z Power Viewer , and vice
versa.
●
Activating the RF frequency sweep, RF level sweep or the list mode instantly deac-
tivates a running "NRP-Z Level Control".
●
A running list or RF sweep mode blocks "NRP-Z Level Control". It can not be acti-
vated.
Also keep in mind that modulated signals may differ from CW signals regarding mean
power and peak power. This affects the operation of "NRP-Z Level Control".
RF Block