Mobile communications device with GPS receiver and common clock source
First Claim
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1. A mobile communications device comprising:
- a communications unit configured to receive communications data from a source, wherein the communications data includes a precision signal; and
a global positioning system (GPS) unit coupled to the communications unit, wherein the GPS unit includes a phase-locked loop having a phase interpolated fractional frequency synthesizer, the phase-locked loop providing a reference signal phased-locked to the precision signal, the reference signal being provided to downconvert a GPS satellite signal.
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Abstract
A mobile communications device using a common oscillator for communication and global positioning system (GPS) functions. In one embodiment, a communications unit receives a precision carrier frequency signal from a source and generates a reference signal that is used to calibrate a common oscillator.
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Citations
26 Claims
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1. A mobile communications device comprising:
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a communications unit configured to receive communications data from a source, wherein the communications data includes a precision signal; and a global positioning system (GPS) unit coupled to the communications unit, wherein the GPS unit includes a phase-locked loop having a phase interpolated fractional frequency synthesizer, the phase-locked loop providing a reference signal phased-locked to the precision signal, the reference signal being provided to downconvert a GPS satellite signal. - View Dependent Claims (2, 3, 4, 5)
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6. A mobile global positioning system (GPS) device, comprising:
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a first antenna for receiving GPS signals; a downconverter coupled to the first antenna, wherein the first antenna provides the GPS signals to the downconverter, wherein the downconverter includes an input for receiving a reference clock signal to convert the GPS signals from a first frequency to a second frequency; a second antenna for receiving a precision carrier frequency signal from a source; an automatic frequency control (AFC) circuit coupled to the second antenna to receive the precision carrier frequency signal and configured to generate a precision reference signal related in frequency with the precision carrier frequency signal; and a phase-locked loop having a phase interpolated frequency synthesizer, the phase-locked loop providing the reference clock signal phase-locked to the precision reference signal. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A mobile communications device, comprising:
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a GPS antenna for receiving GPS signals; a downconverter coupled to the GPS antenna, wherein the GPS antenna provides the GPS signals to the downconverter; a communications unit, including, a communication antenna for receiving a precision carrier frequency signal from a source; and
an automatic frequency control (AFC) circuit coupled to the communication antenna, wherein the AFC circuit provides a reference signal based on the precision carrier frequency signal; andan oscillator coupled to the downconverter, wherein the oscillator provides an oscillator signal phase-locked to the reference signal for mixing with the GPS signals in the downconverter, the oscillator signal being provided by a phase-locked loop having a phase interpolated fractional frequency synthesizer.
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13. A personal communications device comprising:
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a telecommunications unit comprising a device selected from a group comprising, a code division multiple access (CDMA) device, a WCDMA device, a FDMA device, a OFDMA device, a UMTS-compatible device, a UWB-compatible device, a TDMA device, a WiFi device, a PDC device, an iDEN™
device, and a GSM device, wherein the telecommunications unit further comprises a clock source; anda 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 loop for controlling the voltage controlled oscillator, wherein the feedback loop 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. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of clocking GPS receiver operations comprising the steps of:
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receiving a clock signal from a clock source selected from a group comprising, a code division multiple access (CDMA) device clock, a WCDMA device clock, a FDMA device clock, a OFDMA device clock, a UMTS-compatible device clock, a UWB-compatible device clock, a TDMA device clock, a WiFi device clock, a PDC device clock, an iDEN™
device clock, and a GSM device clock;generating a control voltage for controlling a frequency of an oscillator signal generated by a voltage controlled oscillator based upon a feedback signal 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. - View Dependent Claims (23)
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24. A personal communications device comprising:
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means for receiving a telecommunications signal selected from a group comprising, a code division multiple access (CDMA) device means, a WCDMA device means, a FDMA device means, a OFDMA device means, a UMTS-compatible device means, a UWB-compatible device means, a TDMA device means, a WiFi device means, a PDC device means, an iDEN™
device means, and a GSM device means;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. - View Dependent Claims (25, 26)
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Specification