WIDEBAND PHASE LOCKED LOOP TRANSMITTER SYSTEM

摘要

WIDEBAND PHASE LOCKED LOOP TRANSMITTER SYSTEM A phase locked loop including a reference oscillator connected to one input of a loop phase detector the output of which is connected through an integrating low pass filter to a voltage controlled oscillator with the output of the voltage controlled oscillator being mixed with a second frequency and compared to the reference frequency in the loop phase detector. The mixer output is also compared to an output of the reference oscillator shifted 90.degree. in a quadrature phase detector, the output of which controls a lock detector which in turn controls a fixed current sink. The fixed current sink is connected to the integrating low pass filter when the loop is in an unlocked condition so that a linear voltage, ramp signal is applied to the voltage controlled oscillator from the output of the integrating low pass filter. An RF gate attenuates the voltage controlled oscillator output until lock is achieved and subsequent power amplifiers are in operation at which time the RF gate gradually connects the power amplifiers to the output of the voltage controlled oscillator.