Specifications

Lowband Mixer Bias Adjustment
Agilent Technologies
PSA Series Spectrum Analyzers
Test and Adjustment Software
Lowband Mixer Bias Adjustment
The bias currents for the A20 Lowband (1
st
and 2
nd
mixer) internal amplifiers are
adjusted. These are for the 1
st
mixer LO amplifier and IF amplifier, and for the 2
nd
mixer
LO amplifier. The currents are set by measuring voltage differences across 1 ohm sense
resistors. Voltages are monitored on test points on the A13 Front End Driver with a DVM
and are adjusted by supplying data to DACs on A13. The test points are accessible via a
header on the top of A13, so placing A13 on an extender is not necessary. The instrument
cover and top shield must be removed, however.
This adjustment should be performed after replacing the A20 and/or A13 assemblies.
Required Test Equipment
Test Equipment Model Number
E4440A
E4443A, E4445A
E4446A
E4448A
Digital Voltmeter 3458A X X
E4440-60041 Bias Adjustment Board X X
DC Probe 11002A, 11003A X X
Lowband Mixer Bias Adjustment Setup
http://mktwww.soco.agilent.com/field/lp/PSA/PSAcalSWwebhelp/Adjustment/adjustmixbias.htm (1 of 2) [5/29/2003 8:47:24 AM]