Keysight N8976B

Keysight NFA Series Noise Figure Analyzers Service Guide 205
RF Section Troubleshooting (N8976B)
RF Section Description
This assembly contains the following circuits:
— Input Low-pass filter (RF input signals < 3.6 GHz)
— Low Band Preamplifier and Limiter
— RF Mixer #1 (RF input signals < 3.6 GHz)
— 1st LO Sub-system (3.8 GHz to 8.7 GHz)
— 1st IF Amplifier (5122.5 MHz)
— 1st IF Band Pass Filter (A13A1) (low band)
— Mixer #2 (RF input signals 3.6 GHz to 17.1 GHz)
— Microwave Input Amplifier
— Mixer #3 (RF input signals 17 GHz to 34.5 GHz)
— Mixer #4 (RF input signals 34.4 GHz to 44 GHz)
—LO Doubler
— External Mixing Diplexer
A15 Front End Control Assembly
Provides the correct biasing and switch control logic to the following RF
assemblies:
— Input Attenuator A
— Input Attenuator B
—Low Band Switch
— YTF Preselector (Input signals > 3.6 GHz)
— Front End Assembly including switched filter
— High Band Preamplifier
— Low Band Preamplifier
Refer to Chapter 6, “Front End Control Troubleshooting.” for detailed descriptions &
troubleshooting procedures