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US 6,998,922 B2Granted
Phase locked loop modulator calibration techniques
AssigneeBroadcom Corporation
InventorsHenrik T. Jensen, Hea Joung Kim
Life of this patent
Estimating the term…
Abstract
A method for calibrating a phase locked loop begins by determining a gain offset of a voltage controlled oscillator of the phase locked loop. The processing then continues by adjusting current of a charge pump of the phase locked loop based on the gain offset.
Claims20
A method for calibrating a phase locked loop, the method comprises:
- performing an open loop calibration of a voltage controlled oscillator to produce an open loop calibrated voltage controlled oscillator;
- determining a gain offset of the open loop calibrated voltage controlled oscillator of the phase locked loop;
- and
- adjusting current of a charge pump of the phase locked loop based on the gain offset.
1 more element
An auto-calibrating phase locked loop comprises:
- phase and frequency detection module operably coupled to produce an up signal when at least one of phase and frequency of a reference oscillation leads at least one of phase and frequency of a feedback oscillation and to produce a down signal when the at least one of phase and frequency of the feedback oscillation leads the at least one of phase and frequency of the reference oscillation;
- charge pump circuit operably coupled to convert the up signal and down signal into a current signal;
- loop filter operably coupled to convert the current signal into a control voltage;
- voltage controlled oscillator operably coupled to convert the control voltage into an output oscillation, wherein the feedback oscillation is derived from the output oscillation;
- and
- calibration module operably coupled to:
- perform an open loop calibration of the voltage controlled oscillator to produce an open loop calibrated voltage controlled oscillator;
- determine a gain offset of the open loop calibrated voltage controlled oscillator;
- and
- adjust at least one dependent current source of the charge pump based on the gain offset.
7 more elements
A radio transmitter comprises:
- phase and frequency detection module operably coupled to produce an up signal when at least one of phase and frequency of an input modulated signal leads at least one of phase and frequency of a feedback oscillation and to produce a down signal when the at least one of phase and frequency of the feedback oscillation leads the at least one of phase and frequency of the input modulated signal;
- charge pump circuit operably coupled to convert the up signal and down signal into a current signal;
- loop filter operably coupled to convert the current signal into a control voltage;
- voltage controlled oscillator operably coupled to convert the control voltage into a radio frequency oscillation, wherein the feedback oscillation is derived from the radio frequency oscillation;
- and
- calibration module operably coupled to:
- perform an open loop calibration of the voltage controlled oscillator to produce an open loop calibrated voltage controlled oscillator;
- determine a gain offset of the open loop calibrated voltage controlled oscillator;
- and
- adjust at least one dependent current source of the charge pump based on the gain offset.
7 more elements
Dependencies are inferred from the claim text.