Agilent Technologies E8257D PSG User Manual page 297

4. Turn the RF on: set
5. Turn the signal generator's automatic leveling control (ALC) off: press
6. Monitor the RF output amplitude as measured by the power meter.
Press and adjust the signal generator's RF output amplitude until the desired power is
Amplitude
measured by the power meter.
Poor Pulse Performance
For pulse widths <1 microsecond, you may need to do a power search to optimize the pulse
performance of the instrument. Refer to
Setting Power Search Mode
Power search mode executes a power search routine that temporarily closes the ALC, calibrates the
power of the current RF output, and then opens the ALC circuitry. See the Agilent PSG Signal
Generators Key Reference for more information on the Power Search function.
CAUTION There are two "RF During Power Search" settings available for the power search,
Minimum and Normal. The Minimum softkey sets the internal attenuator to its maximum
setting during power search to protect the power sensitive circuits. When the power
search has completed the attenuator is returned to the last attenuator setting before the
power search was executed. The Normal softkey executes the power search without this
added attenuator protection.
A successful power search is dependent on a valid power search reference and the
instrument's ability to level at a set power level without modulation.
There are three power search modes: manual, automatic, and span.
Manual When
search calibration routine for the current RF frequency and amplitude. In this
mode, if there is a change in RF frequency or amplitude, you will need to press
Power Search
Auto When
frequency or amplitude of the RF output is changed.
Span When
calibration routine over a selected range of frequencies at one time. The power
search corrections are then stored and used whenever the signal generator is
tuned within the selected range of frequencies. Span power search settings are
only valid for a single power level.
Use the following steps to set the signal generator to manual fixed power search mode:
1. Press .
Preset
2. Press and enter the desired frequency.
Frequency
3. Press and enter the desired amplitude.
Amplitude
4. Press >
Amplitude ALC Off On
5. Press
Power Search (Manual, Fixed)
maximum setting during power search to protect the power sensitive circuits. Refer to the Key
Help.)
6. Press to On.
RF On/Off
7. Press
Do Power Search
Chapter 13
to On
RF On/Off
"Setting Power Search Mode" on page
is set to Manual, pressing
Power Search
again.
is set to Auto, the calibration routine is executed whenever the
Power Search
is set to Span, pressing
Power Search
to Off.
> . (The Minimum softkey sets the internal attenuator to its
Minimum
.
RF Output Power Problems
Amplitude
283.
executes the power
Do Power Search
executes the power search
Do Power Search
Troubleshooting
> to Off.
ALC Off On
Do
283