Agilent Technologies Option H48 Multiport Test Set Z5623A - Manual (Page 126)

8 -4 Agilent Technologies Z5623A Option H48
Service
Theory of Operation
A2 Controller and A3 Switch Driver Board Theory
The mother and daughter boards provide the bias for the switching
paths for the various ports to the Reflection or Transmission ports. The
front panel display contains an LCD that indicates the switched ports.
A particular test port (1 through 8) can be in one of three states. The
three states are:
• Switched to the forward path
• Switched to the reverse path
• Terminated in 50
Ω
When a port is not connected, it is automatically terminated in 50 Ω.
Only one test port can be connected to any one reflection port and only
one test port can be connected to any transmission port at any given
time.
The test set consists of eight 1x2 switches and six 1x4 switches. The 1x2
switches divide each of the input ports (1 through 8) into two separate
paths.
All switches are electromechanical and are biased according to the
necessary switching path. A user interface through the GPIB and
parallel ports converts the necessary input signals from the user to the
necessary control signals to control the switching paths.
A4 Front Panel Display Theory
The front panel display consists of an LCD. The LCD is divided into two
lines of text. The first line indicates which of the twelve ports are
connected to the forward path. The second line indicates which of the
twelve ports are connected to the reverse path. Control signals and DC
power are provided by a cable connected to the main switch board.
Connector Replacement
The 50
Ω Type-N connectors are available separately. It is possible to
replace them in the field.