Rohde & Schwarz FPL1000 Series, User Manual

Page: 364 / 899

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
364 User Manual 1178.3370.02 ─ 03
RF Input Protection
The RF input connector of the R&S FPL1000 must be protected against signal levels
that exceed the ranges specified in the data sheet. Therefore, the R&S FPL1000 is
equipped with an overload protection mechanism. This mechanism becomes active as
soon as the power at the input mixer exceeds the specified limit. It ensures that the
connection between RF input and input mixer is cut off.
When the overload protection is activated, an error message is displayed in the status
bar ( "INPUT OVLD" ), and a message box informs you that the RF Input was discon-
nected. Furthermore, a status bit (bit 3) in the
STAT:QUES:POW
status register is set.
In this case you must decrease the level at the RF input connector and then close the
message box. Then measurement is possible again. Reactivating the RF input is also
possible via the remote command
INPut:ATTenuation:PROTection:RESet
.
Radio Frequency State .............................................................................................. 364
Impedance ................................................................................................................. 364
Radio Frequency State
Activates input from the RF INPUT connector.
Remote command:
INPut:SELect
on page 670
Impedance
For some measurements, the reference impedance for the measured levels of the
R&S
FPL can be set to 50
Ω
or 75
Ω
.
Select 75
Ω
if the 50
Ω
input impedance is transformed to a higher impedance using a
75
Ω
adapter of the RAZ type. (That corresponds to 25
Ω
in series to the input impe-
dance of the instrument.) The correction value in this case is 1.76 dB = 10 log (75
Ω
/
50
Ω
).
This value also affects the unit conversion (see " Reference Level " on page 385).
Remote command:
INPut:IMPedance
on page 670
7.3.2 Power Sensors
The R&S FPL1000 can also analyze data from a connected power sensor.
● Basics on Power Sensors ..................................................................................... 364
● Power Sensor Settings ..........................................................................................366
● How to Work With a Power Sensor .......................................................................371
7.3.2.1 Basics on Power Sensors
For precise power measurement, up to 4 power sensors can be connected to the
instrument via the optional power sensor interface (on the rear panel) or the USB con-
nectors. Both manual operation and remote control are supported.
Receiving Data Input and Providing Data Output