A11 Low Band Switch; A12 Ytf Preselector; A20 Yto Assembly - Keysight N9040B Option 508 Service Manual

RF Section Troubleshooting (RF/Microwave Analyzers)
RF Section Description

A11 Low Band Switch

This assembly operates across the entire frequency range of the analyzer. The
switch has 3 main functions:
— Switch RF input frequencies from 3 Hz to 3.59 GHz RF Output to A13 RF
— Switch input frequencies from 3.6 GHz to 26.5 GHz Microwave RF Output to
— Contains optional high band preamplifier, which has a typical gain of 30 dB
— Contains protective limiter circuitry.

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,
Preselector Center to manually center the preselector.

A20 YTO Assembly

Provides the 1st LO signal that is required for the A13 RF Front End Assembly.
The 1st LO has a frequency range from 3.50 to 9 GHz. The output power is +13
to +18 dBm. In order to maximize the conversion efficiency and avoid LO
unlock, sufficient LO power must be supplied.
Keysight Technologies N9040B UXA Signal Analyzer Service Guide
Front End Assembly.
A12, YTF Preselector.
and a noise figure from 9 to 12 dB up to 18 GHz.
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