Keysight E8663D, Руководство пользователя

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150 Keysight E8357D/67D & E8663D PSG User’s Guide
Optimizing Performance
Using External Leveling
For example, leveling the CW output of a 30 dB gain amplifier to a level of -10
dBm requires the output of the signal generator to be approximately -40 dBm
when leveled. This is beyond the amplitude limits of the ALC modulator alone,
resulting in an unleveled RF output. Inserting 45 dB of attenuation results in an
ALC level of +5 dBm, well within the range of the ALC modulator.
NOTE
In the example above, 55 dB is the preferred attenuation choice, resulting in
an ALC level of +15 dBm. This provides adequate dynamic range for AM or
other functions that vary the RF output amplitude.
To achieve the optimum ALC level at the signal generator RF output of -40
dBm for an unmodulated carrier, follow these steps:
1. Press Amplitude > Set Atten > 45 > dB.
2. Press Set ALC Level > 5 > dBm .
This sets the attenuator to 45 dB and the ALC level to +5 dBm, resulting in an
RF output amplitude of –40 dBm, as shown in the
AMPLITUDE
area of the
display.
To obtain flatness–corrected power, refer to
“Creating and Applying User
Flatness Correction” on page 151 .
To Level with a mm–Wave Source Module
Millimeter–wave source module leveling is similar to external detector leveling.
The power level feedback signal to the ALC circuitry is taken from the
millimeter–wave source module, rather than the internal signal generator
detector. This feedback signal levels the RF output power at the mm–wave
source module output through the signal generator’s rear panel SOURCE
MODULE interface connector.
For instructions and setups, see
Chapter 12, “ Peripheral Devices”, on page
273 .