Test Set Step Attenuator; The Receiver Block; The Microprocessor; Required Peripheral Equipment - HP 8753D Option 011 Service Manual

The P 85046A/B and P 85047A S-parameter test sets contain the hardware required to
make simultaneous transmission and re ection measurements in both the forward and reverse
directions. An RF path switch in the test set allows reverse measurements to be made without
changing the connections to the device under test.

Test Set Step Attenuator

The 70 dB step attenuator contained in the test set is used to adjust the power level to the
DUT without changing the level of the incident power in the reference path. The attenuator
in the P 85046A/B or P 85047A test set is controlled from the front panel of the analyzer
using the
TTENU TOR PORT 1
he Receiver Block
The receiver block contains three sampler/mixers for the R, A, and B inputs. The signals are
sampled, and down-converted to produce a 4 k z IF (intermediate frequency). A multiplexer
sequentially directs each of the three IF signals to the ADC (analog to digital converter)
where it is converted from an analog to a digital signal to be measured and processed for
viewing on the display. Both amplitude and phase information are measured simultaneously,
regardless of what is displayed on the analyzer.

The Microprocessor

A microprocessor takes the raw data and performs all the required error correction, trace
math, formatting, scaling, averaging, and marker operations, according to the instructions
from the front panel or over P-IB. The formatted data is then displayed.

Required Peripheral Equipment

In addition to the analyzer and the test set, a system requires calibration standards for vector
accuracy enhancement, and cables for interconnections.

A Close Look at the Analyzer's Functional Groups

The operation of the analyzer is most logically described in ve 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 a ect each other's performance.
The power supply functional group consists of the A8 post regulator and the
Power Supply.
A15 preregulator. It supplies power to the other assemblies in the instrument.
The digital control group consists of the A1 front panel and A2 front
Digital Control.
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 and an P 85047A or
85046A/B S-parameter test set if used.
The source group consists of the A3 source, A7 pulse generator, A11 phase lock,
Source.
A12 reference, A13 fractional-N (analog), and A14 fractional-N (digital) assemblies. The A4
RAFT
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or
TTENU TOR PORT 2
softkeys located in the power menu.
Theory of Operation 12-3