Frequency Offset Group Operation (Options 080 And 081); A9 Fractional-N Synthesizer Board (Option 080); A13 Frequency Offset Receiver Assembly (Option 080); A45 And A46 Reference Transfer Switches (Option 081) - Agilent Technologies E8362B Service Manual

Theory of Operation

Frequency Offset Group Operation (Options 080 and 081)

Frequency Offset Group Operation (Options 080 and 081)
The frequency offset group provides the circuitry necessary to phase lock the analyzer
while the source and receiver are tuned to different frequencies.
a simplified block diagram of the frequency offset functional group.
In this section the following assemblies are described:
•

A9 Fractional-N Synthesizer Board (Option 080)

•

A13 Frequency Offset Receiver Assembly (Option 080)

•

A45 and A46 Reference Transfer Switches (Option 081)

A9 Fractional-N Synthesizer Board (Option 080)
The A9 fractional-N synthesizer is identical to the A8 fractional-N synthesizer.
The A9 fractional-N synthesizer board uses the 5 MHz reference signal from the A10
frequency reference board to tune two VCO circuits: one that sweeps from 1500 to
3010 MHz and one that is set to a CW frequency of 2250 MHz. In bands 0–1, these two
signals are heterodyned to produce the output frequencies for A8 listed in
page 5-8. In band 2, the output of the swept VCO is passed through a divide-by-2 circuit to
produce the output frequencies for A8 listed in
VCO signal is sent directly to the synthesizer output.
At the output, an ALC circuit maintains the power level at −5 dBm ± 2 dB for bands 0–1 or
−1.5 dBm ± 2 dB for bands 2–25. In all bands, the output is sent to the A13 frequency offset
receiver assembly.
A13 Frequency Offset Receiver Assembly (Option 080)
The A13 frequency offset receiver assembly consists of a frequency offset receiver board
and a separate receiver module.
The output of the A9 fractional-N synthesizer board is directed to the receiver module
where it is mixed with a signal from the A12 source assembly to produce a phase lock
output signal.
This phase lock signal is sent to a multiplexer on the A35 receiver motherboard, the output
of which is routed to the A11 phase lock board to complete the phase lock loop. Refer to
"Phase Lock Control" on page
A45 and A46 Reference Transfer Switches (Option 081)
The A45 and A46 reference transfer switches are used to direct the reference signal to
either an external reference mixer or directly to the A28 channel R1 first converter
(mixer). Refer to "A27, A28, A29, and A30 Receiver First Converters (Mixers)" on
page 5-21.
This allows an external reference mixer to be switched in or out of the measurement setup
without the need to manually disconnect and reconnect cables.
5-24
Table
5-23.
PNA Series Microwave Network Analyzers
E8362B, E8363B, E8364B
Figure 5-7 on page 5-25
5-2. In all other bands, the swept
Service Guide E8364-90026
is
Table 5-2 on