Specifications

5
Measurement setup
Table 2. Allowable input power to network analyzer
8514B at 8515A at 8517B at
20 GHz 26.5 GHz 50 GHz
0.1 dB compression level for + 8.5 – 3 – 6
test set (at test port) (dBm)
Damage power level at test port (dBm) +17 +17 +17
Table 1. Available output power from network analyzer
RF Source 83621A 83631A 83651A 83651A
8510 Test Set with 8514B with 8515A with 8517B with 8517B, Opt. 007
Frequency (GHz) Test Port Power Levels (dBm)
0.05 +2.5 to –20.5 –3.5 to –26 +1.5 to –21.5 +5 to –21
2 +1 to –22.0 –6 to –29 +0.5 to –23.5 +5 to –21
20 –7.5 to –27 –13.5 to –30 –7.5 to –30 +2 to –23
26.5 –25 to –30 –13.5 to –30 +1 to –24
40 –20 to –30 –3 to –21.5
50 –27 to –30 –13 to –29
Before making an actual measurement it is impor-
tant to know the input and output power levels of
the AUT and the type of calibration required.
Setup
1. Select input power levels
Selecting the proper stimulus settings at the vari-
ous ports of the AUT are of primary concern. If the
small signal gain and output power at the 1 dB
compression point of the amplifier are approxi-
mately known, the proper setting for the input
power level can be estimated. For linear operation,
the input power to the amplifier should be set such
that the output power is approximately 3 to 10 dB
below the 1 dB compression level.
P
input
(dBm) = P
1dB
compression
(dBm)
– Gain
small signal
(dB)–10 dB
For the Agilent 8510C, the power may be varied
continuously within the “available output power
range” indicated in Table 1. If lower power is
required to the AUT, an internal step attenuator
may be varied from 10 to 90 dB in 10 dB steps. It
is advantageous to select a power range that will
accommodate the operation of the amplifier in its
linear region as well as the nonlinear region.
2. Estimate output power
It is also important to know the output power lev-
els from the AUT to avoid overdriving or damaging
the test ports of the network analyzer. External
attenuation may be necessary after an AUT with
high output power to keep the power level below
the specified 0.1 dB compression level of the test
set. For more information see Appendix A, “High-
power measurements.”
When measuring high-gain amplifiers, it is possible
to overload the test port. Overload occurs when
greater than +17 dBm of power is input into either
port. When this happens, “IF OVERLOAD” will be
displayed. At this point, either more attenuation
should be added to the output of the amplifier, or
the input power level should be reduced before
continuing the measurement.