326 N9030B PXA Signal Analyzer Service GuideHardware OptionsA25 Wideband Analog IF Troubleshooting - Option B1X and B85Inputs to the A25 AssemblyA25J101 300 MHz IF signal (from A15J901 Front End Controller)A25J301 2400 MHz reference from A16 Reference Assembly via W34 cableA25J805 Step Calibrator from A3J17 40 MHz Digital IF via W45 cableOutputs from the A25 AssemblyA25J302 2400 MHz Reference OutA25J102 250 MHz IF Out to A3J15 of the 40 MHz Digital IFA25J806 50 MHz Comb Out to A16 Reference assembly A16J726 via W46cableA25J2 ADC Data to 160 MHz Digital IF A26J504 via W44 cableA25 Wideband Analog IF Assembly Theory of Operation - Option B1Xand B85The A25 Wideband Analog IF assembly primary role is to properly filter andapply attenuation or gain to optimize the level going to the ADC and providesufficient pre-filtering to reject images that would otherwise interfere with thesignal of interest. Precision alignments are used to calibrate the filters,attenuators and gain of this assembly. It is not uncommon that the reportedfailure will come from failures reported when an alignment fails for thisassembly. The alignment history file is a good indicator of a failure for thisassembly. This file is a text file that can be edited with Notepad. The file islocated in the following location:E:\AlignDataStore\AlignmentHistory.txtThis file will list all alignments that have passed or failed. Alignments reportinga failure of the WBAIF assembly can in many cases be attributed to failure ofthis assembly. If however these errors follow errors in the RF section of theinstrument, it is possible that additional WBAIF error will appear due tomissing RF Calibration signals and not related to the A25 Wideband IFassembly.Manually troubleshoot the assembly is basically verifying the 300 MHz IF signalis present and at the proper level. In addition you will want to verify input andoutput levels of the various calibration and reference signals.Additionally, the A25 Analog IF has a built in RF Burst Trigger.
