Patent ID: 6226335
Filing Date: 2001-05-01
Classification: H03J

Abstract:
An automatic frequency control system for use in wireless telephone system, comprising:a first counter for counting a number of periods of a controlled frequency received by the frequency control system;a second counter for counting zero crossings of a reference frequency signal received by the frequency control system, the second counter being a non-resettable counter;a count control responsive to the first counter for resetting the first counter and directing a reading of the second counter when the number of periods of the controlled frequency reaches a stored integration period count value;an error detector for tracking a count produced by the second counter and determining a count error and setting the stored integration period count value depending on the count error;an error corrector for receiving the count error and producing an error correction value based on the count error, the error corrector being operative to add the error correction value to the count error to produce a corrected count error;a control value generator for producing a control value based on the corrected count error; anda controlled synthesizer for producing a frequency based on the control value.