186 Keysight Technologies N9040B UXA Signal Analyzer Service Guide
Analog/Digital IF Troubleshooting
A2 Analog IF Assembly Description
A2 Analog IF Assembly Description
When the 10 MHz or 25 MHz IF Path is selected, or when any swept
measurement is made, the analyzer's RF input signal is down converted to a
322.5 MHz intermediate frequency in the A13 RF Front End Assembly. This
322.5 MHz signal is routed through the IF MUX on the A15 Front End Control
Assembly and then input to the A2 Analog I.F. Assembly.
The Analog I.F. down converts the 322.5 MHz signal to a final 22.5 MHz
intermediate frequency. In order to obtain optimal dynamic range and
minimize unwanted spurious signals, this signal is filtered, amplified and
attenuated throughout this assembly. The final 22.5 MHz signal goes through a
series of variable band pass filters each having a specific bandwidth. Three
things determine the signal path and which filters are chosen:
— Instrument resolution bandwidth (RBW) setting
—Application used
—Mode applied
This assembly contains one of the two burst carrier trigger (BCT) circuits for
performing mobile communication measurements. The BCT on the A2
assembly is relatively narrowband. The other BCT circuit is part of the IF MUX
on the A15 Front End Control Assembly and has a much wider bandwidth.
The output of the A2 assembly is a filtered 22.5 MHz signal that goes to one of
the two ADCs on the A3 Digital I.F. Assembly.
Inputs to the A2
322.5 MHz signal (from A15 Front End Control Assembly)
LO Input (300 MHz signal from A16 Reference Assembly)
22.5 MHz Cal Comb Signal (from the A3 Digital IF Assembly)
Outputs from the A2
22.5 MHz signal (to A3 Digital IF Assembly)
RF Trigger Detector (to A3 Digital IF Assembly)
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