Keysight N9923A, Руководство по обслуживанию

Страница: 61 / 138

5-20 Keysight N9923A Service Guide
Theory of Operation
Operation in Modes
5-
For a given mode, the analyzer “remembers” the most recent state of the
current mode when you change to another mode.
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 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, 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.
Power Meter Inactive Inactive 302
Table 5-1 Port Function by Mode
Measurement
Mode
PORT 1
Port
PORT 2 
Port
Required 
Option(s)