HP 8753E manual Built-In ‘I&t Set, Receiver Block, Microprocessor, Required Peripheral Equipment

The Built-In ‘I&t Set

The HP 8753E features a built-in test set that provides connections to the test device, 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 through a 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 cOMeC!ted 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. An RF path switch in the test set allows reverse measurements to be made without changing the connections to the test device.

The Receiver Block

The receiver block contains three sampler/mixers for the R, A, and B inputs The signals are sampled, and mixed to produce a 4 kHz IF (intermediate frequency). A multiplexer sequentially directs each of the three signals to the ADC (analog to digital converter) where it is converted from an analog to a digital signal. The signals are then 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. The data processing sequence is described in “Data Processing” later in this chapter.

Required Peripheral Equipment

Measurements require calibration standards for vector accuracy enhancement (error- correction), and cables for interconnections. Model numbers and details of compatible power splitters, calibration kits, and cables are provided in Chapter 11, “Compatible Peripherals ’

Application and Operation Concepts 6-3