Cat, Na, And Vmm Modes; Power Meter Mode - Agilent Technologies FieldFox N9923AN Service Manual

RF Vector Network Analyzer Theory of Operation
N9923AN Operation in Modes
For most screens under System 7 key, the current measurement mode continues to operate
while the screen is displayed. For instance, while the battery information screen is
displayed, the measurement mode remains active.
There are two exceptions to this:
• the "Options (Licensing)" screen
• "Error Log" screen
When either of these screens is displayed, the firmware is in a special monitor mode and
measurements are suspended.

CAT, NA, and VMM Modes

CAT, NA, and VMM modes make similar measurements (listed below) but are separate
operating modes.
• Return Loss = S11 magnitude
• Insertion Loss = S21 magnitude
Unlike S11 and S21, the values displayed below zero for Return Loss and Insertion Loss
are not negative.
There is no user control of the output power level directly out of the source synthesizer on the
A4 RF board.
The only user control of output power level is the high/low setting on the PORT 1 Atten,
45 dB in or out.
Measurements in VMM mode are made at a single frequency.

Power Meter Mode

All measurement circuitry is switched to the low power state during PM (power meter)
mode. This is the mode with the lowest power dissipation.
The analyzer has no power output capability in this mode. The analyzer essentially
functions as a display for a USB power sensor.
Service Guide N9923-90005 5-19