A9 Input Attenuator A; A10 Input Attenuator B; A11 Low Band Switch; A12 Ytf Preselector - Keysight N8973B Service Manual

RF Section Troubleshooting (N8976B)
RF Section Description

A9 Input Attenuator A

This assembly has two 2 dB attenuator sections, a 6 dB attenuator section, and
a cal signal input port.

A10 Input Attenuator B

This assembly has a total of 60 dB of attenuation to control the signal level into
the Low Band Switch assembly. There is a 10 dB, 20 dB, and 30 dB section in
the A10 assembly. Total input attenuation with the A9 and the A10 combined is
60 dB in 2 dB steps).

A11 Low Band Switch

This assembly operates across the entire frequency range of the analyzer. The
switch has 3 main functions:
—
— Switch input frequencies from 3.6 GHz to 44 GHz Millimeter-Wave RF
— Contains standard optional high band preamplifier, which has a typical gain

A12 YTF Preselector

The YTF Preselector is used for input frequencies greater than 3.6 GHz. Signals
less than 3.6 GHz bypass the YTF assembly and are routed to the low band
input of the A13 RF Front End Assembly. The YTF Preselector is a YIG tunable
bandpass filter whose main purpose is to track the input signal and to filter out
unwanted spurious or image response signals. The YTF Preselector has a 3 dB
bandwidth greater than 40 MHz and an insertion loss of ~ 6.5 dB.
The preselector requires centering for optimum amplitude accuracy. The Auto
Align routine will perform a rough centering during the preselector two point
tuning algorithm. However, when troubleshooting, press Amplitude, Signal
Path, Presel Ad just to manually center the preselector.
Keysight NFA Series Noise Figure Analyzers Service Guide
Switch RF input frequencies from 3 Hz to 3.59 GHz RF Output to A13 RF
Front End Assembly.
Output to A12, YTF Preselector.
of 35 dB to 40 dB and a noise figure from 9 to 23 dB up to 44 GHz.
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