A15 Front End Control Description; Purpose - Keysight n9020a 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 options installed, one of two different A15 Front End
Control board assemblies may be installed. The standard A15 Front End
Control assembly ("FEC") can only control the high band preamplifier options
(P08, P13 and P26) and the electronic attenuator option (EA3). The A15
Enhanced Front End Control assembly ("EFEC") can also control the IF Out
options (CR3 and CRP), the microwave preselector bypass option (MPB), and
provide the IF signal for analysis bandwidth options ≥ 40 MHz (B40, B85, B1A,
and B1X).
assemblies in the analyzer.
locations within the analyzer.
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