Rohde & Schwarz NRT 1080.9506.02/.62, Руководство по эксплуатации

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NRT CORRection Menu
1080.9506.02 2.35 E-8
Consideration of cable losses
After defining the reference plane the NRT requests the entry of the cable loss (OFFSET) between the
sensor and the measurement point actually desired:
CORRection - MEAS.POS - LOAD
(SOURCE) - OFFSET:
Unit: dB
Preset: depends on the sensor used.
IEC/IEEE command:
:INPut<n>:PORT:OFFSet <Attenuation in dB>
Once the entry is terminated the power and matching values are corrected as if the measurement was
carried out at the inaccessible measurement point. The entered cable loss can be indicated between the
bar graphs in the middle of the display (see Section 2.5.10).
Example 1: Measurement of the output power of a transmitter. The sensor is connected to the output of
the transmitter via a short cable with a transmission loss of 0.45 dB. Appropriate setting of
the NRT: Measurement position "SOURCE" with an offset value of 0.45 dB. If no transmis-
sion loss
(OFFSET) is taken into account the measured output power of the transmitter is
0.45 dB (i.e. 10 %) smaller than the real value!
Example 2: Measurement of the matching of an antenna. The sensor is connected to the input of the
antenna via a longer cable with a transmission loss of 1.2 dB. Appropriate setting of the
NRT: Measurement position "LOAD" with an offset value of 1.2 dB. If no transmission loss
(OFFSET)
is taken into account the measured return loss of the antenna is 2.4 dB higher
than the real value!
G
OFFSET (SOURCE)
in dB OFFSET (LOAD)
in dB
Position
Po
w
e
r
Reverse
Forward
Re
tu
rn
l
o
s
s
G
Measurement point "SOURCE"
Measurement point "LOAD"
OFFSET (SOURCE)
in dB OFFSET (LOAD)
in dB
Fig. 2-7 Definition of the measurement position
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