User`s guide

110 Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide
Optimizing Performance
Using Unleveled Operating Modes
Using Unleveled Operating Modes
Figure 5-23 Power Search and ALC Off Softkeys
ALC Off Mode
Turning ALC off deactivates the signal generator’s automatic leveling circuitry. Turning ALC off is
useful when the modulation consists of very narrow pulses that are below the pulse width
specification of the ALC or when up converting external IQ signals and the modulation consists of
slow amplitude variations or bursts that the automatic leveling would remove or distort. When using
the internal IQ baseband generator, the best technique is to use the ALC hold marker function vs.
ALC off for the types of signals just described.
NOTE After the ALC has been turned off, power search must be executed to set the proper output
power level requested on the front panel. Power search is executed automatically by default,
but the these settings can be overridden by using the Manual mode
Available only when
ALC = Off
Available only when
Power Search Reference =
Available only when
Power Search = Span
Auto: The calibration routine executes whenever
output frequency or amplitude changes.
Span: Pressing Do Power Search executes the
power search calibration routine once over a
selected frequency range.
The corrections are stored and used whenever you
tune the signal generator to within the calibrated
frequency range.
For details on each key, use key help
as described on see page 42.
RMS: Value is a DC
bias equivalent to the
value derived from the
file header or the
calculated value from
the current I/Q data.
Fixed: Uses a fixed 0.5
Vrms value (Same
value is used with Ext
I/Q data).
Manual: Allows user to
specify the DC bias
voltage value
(0–1.414 Vrms).
Modulated: Uses the
AC bias from the actual
modulating signal.
Manual
User: Enables the
user to set the
signal generator
frequency settings.
Full: The signal
generator selects
its full frequency
range for the power
search.
Only available when
I/Q is on.
These
softkeys are
only active
when an ARB
waveforms is
playing in
memory.
Manual: User must explicitly execute a power
search to calibrate the open loop ALC level.
Note:
1) This feature is not available on N5183A.
2) This feature is only available in instruments
beginning with serial number 4818 or greater or
and with Option 099.