Personal communications device with GPS receiver and common clock source
AssigneeSiRF Technology, Inc.
InventorPaul A. Underbrink
Life of this patent
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Abstract
The invention is directed to a personal telecommunications device having both global positioning systems (GPS) and telecommunications provisions which share a common clock source. GPS provisions include a feedback loop for controlling an oscillator that generates a GPS system signal based upon the common clock signal. The feedback loop includes a frequency synthesizer for generating a feedback control signal, a phase comparator for generating a control signal in accordance with the feedback signal and the common clock signal, and a loop filter for processing and outputting the control signal to the oscillator to control the frequency of GPS system signals.
Claims14
A personal communications device comprising:
- a telecommunications unit comprising a code division multiple access (CDMA) device, wherein the telecommunications unit further comprises a clock source;
- and
- a global positioning system (GPS) receiver, wherein the GPS receiver comprises a voltage controlled oscillator for generating a GPS system clock signal based upon the clock source, and a feedback loon for controlling the voltage controlled oscillator, wherein the feedback loon comprises,
- a phase comparator for generating a control signal in accordance with the feedback signal and the clock source;
- and
- a loop filter for processing the control signal and outputting the control signal to the voltage controlled oscillator.
A method of clocking GPS receiver operations comprising the steps of:
- receiving a clock signal from a clock source;
- generating a control voltage for controlling frequency of an oscillator signal generated by a voltage controlled oscillator based upon a feedback signal generated by a frequency synthesizer;
- and
- generating a system clock signal of a particular frequency in response to the control voltage, wherein the frequency synthesizer generating the feedback signal includes,
- receiving the system clock signal;
- frequency dividing the system clock signal by at least two integer values to generate a fractional-N divider signal over a discrete time period;
- generating a variably delayed signal based upon the fractional-N divided signal within the discrete time period;
- and
- comparing a phase of the variably delayed signal and a reference signal and varying the system clock signal according to a detected phase difference.
A personal communications device comprising:
- means for receiving a telecommunications signal;
- means for receiving a global positioning system (GPS) signal comprising an oscillator for generating a GPS system clock signal and a feedback loop for generating and providing a control signal to the oscillator;
- and
- means for generating a clock source signal to be provided to the means for receiving a global positioning system (GPS) signal and the means for receiving a telecommunications signal, wherein the feedback loop comprises,
- a frequency synthesizer for generating a feedback signal;
- and
- a phase comparator for generating a control signal in accordance with the feedback signal and the clock source signal.
Dependencies are inferred from the claim text.