Specifications

84 Chapter 10
Using External Millimeter Mixers (Option AYZ)
Setting Harmonic Mixer Bias Current
Using External Millimeter Mixers
(Option AYZ)
Setting Harmonic Mixer Bias Current
The Agilent 11970 Series harmonic mixers do not require an external
bias current. Harmonic mixers that require bias can also be used. The
conversion loss calibration data for mixers requiring an external bias
current are most accurate when the correct bias conditions are applied.
Step 1. Before continuing, complete the previous procedure “Making
Measurements With Agilent 11970 Series Harmonic Mixers” on page 82
to set up the analyzer for external mixing in the band of interest.
Step 2. Activate the bias:
Press
Input/Output, Input Mixer, Mixer Config, Mixer Bias (On)
A +I or
−I appears in the display annotation indicating bias is on.
Step 3. Enter the desired bias current in mA.
The mixer bias is supplied from the IF INPUT port of the analyzer.
CAUTION The open-circuit bias voltage can be as great as ±3.5 V through a source
resistance of 500 ohms. Such voltage levels may appear when recalling
an instrument state in which a bias setting has been stored.
NOTE The bias value that appears on the analyzer display is expressed in
terms of short-circuit current (that is, the current that would flow if the
IF INPUT were shorted to ground). The actual current flowing into the
mixer is less.