Discrete-time amplitude control of voltage-controlled oscillator
AssigneeNational Semiconductor Corporation
InventorsJayendar Rajagopalan, Rob Butler
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Abstract
Periodically, sensed amplitude for the output signal of a voltage-controlled oscillator is compared to a reference and biasing of the voltage-controlled oscillator is correspondingly set, thereby controlling amplitude of the voltage-controlled oscillator output signal. Process and temperature dependencies of the amplitude are eliminated while achieving low phase noise and large signal-to-noise ratio in the output signal, and consequently low phase noise.
Claims20
A voltage-controlled oscillator discrete-time amplitude control system comprising:
- a voltage-controlled oscillator;
- and
- a control circuit sensing an amplitude of an output of the voltage-controlled oscillator and adjusting operation of the voltage-controlled oscillator, if necessary, at discrete intervals.
A method of discrete-time amplitude control system for a voltage-controlled oscillator, the method comprising:
- operating a voltage-controlled oscillator;
- and
- sensing an amplitude of an output of the voltage-controlled oscillator and adjusting operation of the voltage-controlled oscillator, if necessary, at discrete intervals.
A voltage-controlled oscillator discrete-time amplitude control system comprising:
- a voltage-controlled oscillator producing a differential output signal;
- a control circuit sensing an amplitude of the output signal and generating a control signal for controlling biasing of the voltage-controlled oscillator;
- and
- a biasing circuit biasing the voltage-controlled oscillator based upon the control signal,
- wherein the biasing of the voltage-controlled oscillator is adjusted, if necessary, at a predetermined point within a recurring period.
Dependencies are inferred from the claim text.