Specifications

18
Example 3: Residual measurement of an Agilent 8347A
amplifier
In this configuration, the phase detector constant
will be measured with the DUT configured into the
measurement. If the power levels into the Agilent
70420A are the same as in Example 2, the phase
detector constant will also be similar.
1. Connect the components as shown in Figure 2-13.
The amplifier after the pulse modulator may be
necessary to set the appropriate power levels
at the signal and reference inputs of the phase
noise measurement system. The attenuator prior
to the amplifier-under-test may be necessary to
adjust the power level at the input to the phase
noise test set and keep the amplifier out of com-
pression. Do not connect the signal paths to the
phase noise measurement system at this step.
2. Set up stimulus source.
a) Carrier frequency: 1.5 GHz
b) Amplitude: Set power levels at the connectors
to the 70420A detector input ports:
Ref Input: 10 dBm
Signal Input: 0 dBm
3. Set up pulse generator.
a) Duty Cycle = 10%
b) PRF = 20 kHz
c) Connect pulse generator output to the pulse
modulator.
4. Set power in to DUT (8347A).
a) Measure the power at the input to the DUT
with the RF spectrum analyzer.
b) Attenuate the signal to place the amplifier
in its linear range.
c) Set the ALC selection for the amplifier to
“OFF.”
d) Measure the power output of the DUT.
e) Attenuate the signal to set the power level
to approximately 0 to +5 dBm at the input
to the phase detector.
5. Set up calibration source.
a) Carrier frequency: 1.500005000 GHz
b) Amplitude: Set spur power level at the 70420A
reference input port –40 dBc @ 5 kHz from
CW carrier.
c) Disconnect calibration signal from coupler.
Figure 2-13. Configuration diagram for amplifier pulsed carrier residual phase
noise measurement
Pulse
Gen
83732B
Stimulus
Source
Pulse
Modulator
Splitter
Attenuator
E5500
8437A
Input
Ref
Input
Phase
Shifter
16 dB Coupler
Amplifier
8663A
Calibration
Source
DUT