Externally Leveling the Synthesizer

In externally leveled operations, the output power from the synthesizer is detected by an external sensor. The output of this detector is returned to the leveling circuitry, and the output power is automatically adjusted to keep power constant at the point of detection.

Leveling with Detectors/Couplers /Splitters

Figure l-11 illustrates a typical setup for external leveling. When externally leveled, the power level feedback is taken from the external negative detector input rather than the internal detector. This feedback voltage controls the ALC system to set the desired RF output. Refer to Figure A-l in Chapter 2, for a block diagram of the synthesizer’s ALC circuitry.

SYNTHESIZER

NEGATIVE

LEVELED OUTPUT

b

Figure l-1 1. ALC Circuit Externally Leveled

Getting Started Advanced 1-23