Abstract: A system for extracting and compensating for reference frequency error adapted for use with a communication system. The system includes a frequency generator for outputting a reference signal of a first frequency. The frequency generator has acontrol input for adjusting the first frequency in response to a control signal. A receive circuit receives an input signal and provides an output signal having a first and second component in response thereto. An error extraction circuit provides an error value based on a phase difference between the first component and the second component, and provides the control signal in response thereto. The error extraction circuit preferably includes a positive error counting circuit for generating a positive count when the first component lags the second component and a negative error counting circuit for generating a negative count when the first component leads the second component.

Abstract: A power control circuit for use with a closed loop transmitter such as a cellular telephone. The inventive circuit includes a first element for providing a transmitter output signal. A second element serves to receive a power level signal. A third element is included for adjusting the transmitter output signal in response to the power level signal in accordance with a first scale factor over a first range if the power level signal is below a first threshold and for adjusting the transmitter output signal in response to the power level signal in accordance with a second scale factor over a second range if the power level signal is not below the first threshold. In the illustrative embodiment, the system is adapted for use in a mobile station of a cellular telephone system to which a power level control signal is supplied by a base station thereof. The first element is a variable gain amplifier, the second element is a microprocessor.