SEMICONDUCTOR MICROWAVE AMPLITUDE AND PHASE MODULATOR

摘要

The drive power required to maintain a constant modulation index as the rf carrier power was varied from 0.22 mW to 2.5 mW was experimentally determined for the PIN amplitude modulator. A linear relation was found to exist between the modulation drive and the rf carrier power levels.nEffort to stabilize the varactors for the phase modulator by coating the semi-conductor surface with a thin dielectric film was continued. Ciba Araldite 6005 epoxy has been found to be effective in enhancing varactor stability. Experiments to encapsulate the varactor in an inert atmosphere with Mylar windows or dielectric plucs were initiated.nTheoretical analysis indicates that the voltage-dependent resistance of a properly biased PIN diode can be used to achieve phase modulation consistent with the program requirements.