Agilent X-Series Signal Generators User’s Guide 121
Optimizing Performance
Using Unleveled Operating Modes
The FIXED, RMS, and MANUAL references use a DAC to apply the reference voltage and do not
require the IQ signal to be present.
NOTE The MXG/EXG reference voltage is designed to operate between 0.1 Vrms to 1 Vrms
nominally, but it can overrange to 1.414 Vrms. (The RMS can overrange to 1.414, if the
constant values are loaded manually and all “1”s are entered for the I and Q values.) See
also “Saving a Waveform’s Settings & Parameters” on page 155.
CAUTION The minimum reference level that results in a successful power search is dependent on
RF Frequency, RF Amplitude, and Temperature. An MXG/EXG power search using a
reference level of 0.1 Vrms for 0 dBm at 1 GHz may fail.
Power Search Settings
For the power search routine to execute, the instrument must be in the following conditions:
• The I/Q modulation enabled On.
• The RF output enabled On.
• The Automatic Leveling Circuitry deactivated (Off).
• The RF Blanking set to On.
This function prevents power spikes during the power search (refer to “Using the RF Blanking
Marker Function” on page 172.)
• When using summing for the internal Arb and the external I/Q, all four power reference modes
are available (e.g. Fixed, RMS, Manual, and Modulated).
• When using the external IQ inputs, use the MANUAL reference mode, and make sure the external
I/Q signal is present when executing a power search. If the external I/Q signal is not present, the
power search will fail.
Example: Automatic Power Search
1. Preset the signal generator.
2. Set the desired frequency.
3. Set the desired amplitude.
4. Turn the RF output on.
5. Deactivate the signal generator’s automatic :
Press AMPTD > ALC Off On to highlight Off
Deactivating the signal generator’s automatic leveling control is a significant instrument change
that automatically initiates a power search.
When set to Auto, power search automatically executes when a significant instrument setting changes.
The Do Power Search feature enables you to decide when to execute a power search to compensate
for changes, such as temperature drift or a change in the external input.
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