A Close Look At The Analyzer's Functional Groups - Agilent Technologies 8753ET Service Manual

A Close Look at the Analyzer's Functional Groups

The operation of the analyzer is most logically described in five functional groups. Each
group consists of several major assemblies, and performs a distinct function in the
instrument. Some assemblies are related to more than one group, and in fact all the groups
are to some extent interrelated and affect each other's performance.
• Power Supply: The power supply functional group consists of the A8 post regulator
and the A15 preregulator. It supplies power to the other assemblies in the instrument.
• Digital Control: The digital control group consists of the A1 front panel and A2 front
panel processor, the A9 CPU, the A16 rear panel, the A18 display and the A19 graphics
system processor (GSP). The A10 digital IF assembly is also related to this group. These
assemblies combine to provide digital control for the analyzer.
• Source: The source group consists of the A3 source, A7 pulse generator, A11 phase lock,
A12 reference, A13 fractional-N (analog), and A14 fractional-N (digital) assemblies. The
A4 sampler is also related since it is part of the source phase lock loop. The source
supplies a phase-locked RF signal to the device under test.
• Signal Separation:
8753ET
Reflected power is separated from incident power by the A21 dual directional coupler
and sent to the A sampler. Power transmitted through the device under test is routed
through the transmission port to the B sampler.
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The signal separation group performs the function of an S-parameter test set, dividing
the source signal into a reference path and a test path, and providing connections to the
device under test. It consists of the A24 transfer switch, the A21 test port 1 coupler, and
the A22 test port 2 coupler.
• Receiver: The receiver group consists of the A4/A5/A6 sampler/mixers and the A10
digital IF. The A12 reference assembly and the A9 CPU are also related. The receiver
measures and processes input signals for display.
The following pages describe the operation of each of the functional groups.
Chapter 12
A Close Look at the Analyzer's Functional Groups
Theory of Operation
12-5