Data acquisition and parameters (Sensor menu)
R&S NRP
1144.1400.12 4.22
E-2
Measurement ranges
R&S NRP sensors do not have measurement ranges in the conventional sense. Instead, the
R&S NRP-Z1x and R&S NRP-Z2x multipath diode sensors have several measurement paths with dif-
ferent sensitivities which are always simultaneously active. The
Auto
range function automatically se-
lects the most suitable paths, i.e. those that are neither overdriven or underdriven. The final measure-
ment result for the “crossover” of the two measurement paths is derived from the measured values for
both paths. There are only a few cases where it makes sense to intervene in this process, e.g. test sig-
nals with a large peak-to-average ratio.
To prevent measurement paths which have been overdriven by signal peaks from being included in the
evaluation, the
User defined Crossover
function can be used to reduce levels in the measurement path
crossover. The effect of setting the
Level
parameter to –6 dB, for example, is to reduce the crossover by
6 dB. This corresponds to an increase in drive range of the same magnitude, which reduces measure-
ment deviations due to modulation to 25% of the original value.
While large signal characteristics improve as the crossover level drops, the effects of zero deviations
and intrinsic noise on the result become more marked. The reason for this is that above the crossover
ranges the less sensitive of the two measurement paths is underdriven. This is why there is little point in
changing the crossover level by more than 10 dB.
If you want to turn off the
Auto
range function, e.g. to test the drive range of a path, you can define one
of the three paths as the measurement range with
Path
.
Thermal sensors (R&S NRP-Z5x) have only one measurement range over the whole dynamic range.
No facilities for switching between measurement ranges are, therefore, provided.
Sensor menu
:
Range… –
( )
ä
ä
Fig. 4-19
Range dialog box
A | B | C | D
–
( )
ä
↔
ä
Tabs for selecting the sensor.
Auto –
( )
ä
ä
For turning the
Auto
range function on/off.
Remote Control
[SENSe[1..4]][:POWer][:AVG]:RANGe:AUTO[?] ON | OFF
Path –
( )
1
2
3
ä
ä
For selecting a measurement path when the
Auto
range function is off.
Remote Control
[SENSe[1..4]][:POWer][:AVG]:RANGe[?] 0 | 1 | 2
User def'd
–
( )
Crossover
ä
ä
Activates a decrease in the crossover range.
Sensor
Range…
