Output Power; Understanding The Power Ranges - Agilent Technologies 8753ET User Manual

Operating Concepts

Output Power

Output Power

Understanding the Power Ranges

The built-in synthesized source contains a programmable step attenuator that allows you
to directly and accurately set power levels in eight different power ranges. Each range has
a total span of 25 dB. The eight ranges cover the instrument's full operating range from
+10 dBm to −85 dBm. In addition, some amount of overrange and underrange is permitted
beyond the stated limits. Performance outside of the range limits varies from one analyzer
to another and is not specified. A power range can be selected either manually or
automatically.
Automatic mode
If you select
PWR RANGE AUTO
operating range of the instrument and the source attenuator will automatically switch to
the corresponding range.
Each range overlaps its adjacent ranges by 15 dB, therefore, certain power levels are
designated to cause the attenuator to switch to the next range so that optimum (leveled)
performance is maintained. These transition points exist at −10 dB from the top of a range
and at +5 dB from the bottom of a range. This leaves 10 dB of operating range. By turning
the RPG knob with
PORT POWER
switch as these transitions occur. See the specifications and characteristics chapter in the
reference guide for the analyzer's power limits.
Manual mode
If you select
PWR RANGE MAN
manually select the power range that corresponds to the power level you want to use. This
is accomplished by pressing the
eight available ranges. The active power will always be reset to be within this range. In
this mode, you will be able to select power levels above or below the range limits. The
factory limits on setting power level are +6 dB above the maximum range power and −12
dB below the minimum range power. Typical performance for power overrange is 2 dB
above the maximum (more at lower frequencies and less at higher frequencies) and typical
under range is 6 dB. An under-range condition may cause a phase lock lost message to be
displayed.
When a calibration is active, the power range selection is switched from auto to manual
mode, and PRm appears on the display. This feature is necessary to maintain accuracy once
a measurement calibration is activated.
7-10
, you can enter any power level within the total
being the active function, you can hear the attenuator
, you must first enter the power ranges menu and
softkey and then selecting one of the
POWER RANGES