Technical data

User’s and Service Guide 6-23
Servicing the Test Set
Theory of Operation
Theory of Operation
The theory of operation begins with a general description of the
Agilent 87050A Option H15 multiport test set. This is followed by more
detailed operating theory. The operation of each group is described
briefly, to the assembly level only. Detailed component level circuit
theory is not provided.
System Theory
The test set consists of three main components:
• power supply
• front panel display
• controller interface mother board
The purpose of the power supply is to provide power to both the front
panel display and the main switch board. The front panel display serves
to indicate the switching paths to the user. Finally, the controller
interface mother board does the actual switching between the different
ports.
A1 Power Supply Theory
The switching power supply provides regulated dc voltages to power all
assemblies in the test set. A dc cable provides power to the main switch
board. A connector from the main switch board to the front panel
display provides dc power and control signals to the front panel. The
power supply provides the following voltages: +24 V, +12 V, and +5 V.
A2 Front Panel Display Theory
The front panel display consists of an LCD. The LCD is divided into two
sections, Reflection and Transmission. The first section indicates which
of the ten ports is connected to the Reflection port. The second section
indicates which of the sixteen ports is connected to the Transmission
port. Control signals and dc power are provided by a cable connected to
the main switch board.