HP 8753D Option 011 Service Manual page 327

Signal Separation
External est Sets
set contains a switched frequency doubler to double the P
The HP 85047A S-parameter test
8753C source frequency. A portion of the RF signal is coupled to the analyzer R input for
reference. (For an P 8753D Option 011 combined with Option 006, the frequency doubler
is bypassed since the analyzer's source is capable of generating a swept RF signal up to 6
G z.) The remaining signal is routed through a 70 dB programmable step attenuator to
the directional couplers for re ection and transmission measurements. The couplers allow
detection of the signal from 300 k z to 6 G z. These couplers provide low insertion loss
between the RF input and the test ports. Two bias tees supply external biasing for active
devices. An P 8753D Option 006/011 is required for use with the P 85047A test set.
Figure 12-9a shows a simpli ed block diagram of the P 85047A.
contains a power splitter to divert a portion of the
The HP 85046A/B S-parameter test set
incident signal to the R input of the analyzer for reference. The remainder of the incident
signal is routed through a switch to one of two directional bridges at the measurement ports.
The RF path switch is controlled by the analyzer to enable switching between forward and
reverse measurements. A 70 dB step attenuator in the test set, also controlled from the
analyzer, adjusts the power level to the DUT without changing the level of the incident
power in the reference path. Two bias tees are included, for external biasing of active devices
connected to the test ports. Figure 12-9b shows a simpli ed block diagram of the P
85046A/B.
contains a power splitter to divert a
The HP 85044A/B transmission/re ection test set
portion of the incident signal to the R input of the analyzer. The remainder of the incident
signal is routed through a directional bridge to the measurement port. The test set includes
a manually controlled 70 dB step attenuator, and a bias tee for external biasing of active
devices connected to the test port. A simpli ed block diagram of the P 85044A/B is shown
in Figure 12-9c.
can be used instead of a test set for transmission
An HP 850C/D or 667A power splitter
measurements only.
12-18 Theory of Operation RAFT
3/21/106 15:14
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