A15 Front End Control Description; Purpose - Keysight N8973B Service Manual

Front End Control Troubleshooting

A15 Front End Control Description

A15 Front End Control Description

Purpose

The A15 Front End Controller board functionality can be broken down into (3)
main categories
1. Provides switch control logic and bias voltages to the major RF front end
2. Contains on board circuitry providing various signal outputs to other
3. Provides control logic for various instrument options within the analyzer.
These signals are routed to and from the A15 via ribbon cables, wiring
harnesses and coaxial cables. The RF front end assemblies require the correct
control logic and bias in order to function properly. If the voltages from the A15
are not correct, the RF input signals will most likely be displayed at an incorrect
power level if they even get displayed at all.
Depending upon the model number, one of two different A15 Front End
Control board assemblies may be installed. The "EFEC-Lite" is installed in the
N8973B, 74B, and 75B. The Enhanced Front End Control assembly ("EFEC") is
installed in the N8976B.
230
assemblies in the analyzer.
locations within the analyzer.
Keysight NFA Series Noise Figure Analyzers Service Guide