Keysight N8976B

200 Keysight NFA Series Noise Figure Analyzers Service Guide
RF Section Troubleshooting (N8976B)
RF Section Description
RF Section Description
This section covers only the N8976B NFA model.
The RF input signal can be routed through four different front end signal paths.
These various paths are switched in and out based on where the signal
analyzer center frequency is tuned.
1. Low band RF path is used when the input frequency is ≤ 3600 MHz
2. High band RF path #1 is used when the input frequency is > 3.6 GHz
to 17.1 GHz
3. High band RF path #2 is used when the input frequency is > 17 GHz to
34.5 GHz
4. High band RF Path #3 is used when the input frequency is > 34.4 GHz to
44 GHz
The RF section is designed to convert RF input signals to an intermediate
frequency that is present at the RF output of the A13 Front End assembly. This
intermediate frequency (IF) depends on installed options and the IF path
selected. This chapter will assume the default operation in Spectrum Analyzer
mode. Therefore the IF frequency will be 322.5 MHz.
IF Path IF Mode
10 MHz (standard) 322.5 MHz Spectrum Analyzer or IQ Analyzer
25 MHz (standard Option B25) 322.5 MHz IQ Analyzer