The Receiver Block; The Microprocessor; Required Peripheral Equipment - HP 8753E Service Manual

The Built-In lkst Set
The HP 8753E features a built-in test set that provides the signal separation
capability for the device under test, as well as to the signal-separation devices.
The signal separation devices are needed to separate the incident signal from
the transmitted and reflected signals. The incident signal is applied to the R
channel input via an external jumper cable on the front panel. Meanwhile,
the transmitted and reflected signals are internally routed from the test port
couplers to the inputs of the A and B sampler/mixers in the receiver. Port 1 is
connected to the A input and port 2 is connected to the B input.
The test set contains the hardware required to make simultaneous transmission
and reflection measurements in both the forward and reverse directions. A
solid-state transfer switch in the built-in test set allows reverse measurements to
be made without changing the connections to the device under test.

The 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 kHz 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 HP-IB. The formatted
data is then displayed.

Required Peripheral Equipment

In addition to the analyzer, a system requires calibration standards for vector
accuracy enhancement, and cables for interconnections.
Theory of Operation 123