Patent ID: 6225864
Filing Date: 2001-05-01
Classification: H03C,H03F,H04B

Abstract:
An RF amplifier system having a phase modulator for varying the phase of an RF signal, comprising:an RF source for providing an RF signal made up of a first train of pulses exhibiting a fixed frequency and fixed duty pulse cycle and wherein each pulse is of a fixed amplitude and duration;said modulator including:integrating means for converting each pulse cycle of said RF signal into a dual slope symmetrical ramp signal which varies in magnitude from a minimum level to a maximum level and then back to said minimum level for each pulse cycle;means for providing a first level signal and a second level signal equally spaced from a reference level wherein said reference level is midway between said minimum and maximum levels of said ramp signal;dual slope comparing means for comparing said dual slope ramp signal with said first and second level signals and providing a first pulse signal for a time duration corresponding with the time duration that said ramp signal exceeds said first level signal and a second pulse signal for a time duration corresponding with the time duration that said second level signal exceeds said ramp signal;first and second pulse generators for respectively receiving said first and second pulse signals and providing therefrom first and second trigger pulses;bistable means responsive to said first and second trigger pulses to be in respective first state in response to a first trigger pulse and a second state in response to a second trigger pulse and providing an output RF signal made up of a second train of pulses of said fixed frequency and said fixed duty cycle of said first pulse train and being shifted in phase therefrom by an amount related to the magnitude of said first level signal or said second level signal.