Patent ID: 6606003
Filing Date: 2003-08-12
Classification: H03L

Abstract:
In a system that requires at least one voltage controlled oscillator having (I) a nominal frequency that is produced in response to a given voltage and (ii) a corresponding voltage-to-frequency transfer function, a method of dynamically calibrating the at least one voltage controlled oscillator during initialization or at one or more subsequent times to compensate for variation, from one voltage controlled oscillator to another, in the given voltage that produces the nominal frequency, the corresponding voltage-to-frequency transfer function, or both, the method comprising:an act of counting a reference frequency over a one or more first time intervals; an act of iteratively applying a plurality of control input voltages to said least one voltage controlled oscillator; an act of counting a variable frequency produced by said at least one voltage controlled oscillator in response to each of the control input voltages, wherein the counting occurs over one or more second time intervals; an act of calculating the variable frequency produced in response to each of control input voltages based on the reference frequency count, the variable frequency count, the one or more first and second time intervals, and the reference frequency; an act of comparing each variable frequency, produced in response to the control input voltages, to the nominal frequency to determine a specific one of the control input voltages that produces a nominal output frequency for the selected voltage controlled oscillator; a step for storing the control input voltages in a table that represents at least a portion of voltage-to-frequency transfer function of said at least one voltage controlled oscillator, wherein the specific one of the control input voltages that produces the nominal output frequency is stored as a zero point in the table; and a step for using the stored transfer function to calibrate the output of said at least one voltage controlled oscillator one or more times.