Upstream/downstream local oscillator methods and structures for wireless communication system transceivers
AssigneeCalifornia Amplifier, Inc.
InventorsJames J. Hornsby, Kris Kelkar
Life of this patent
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Abstract
Local-oscillator systems for wireless communication systems are realized with oscillator networks that are phase locked to a bit timing clock. Two of the networks provide first and second phase coherent local-oscillator signals respectively to a receiver and transmitter of a transceiver. A third oscillator system forms a phase lock loop about one of the other networks and preferably includes a crystal to enhance short term stability. Because they track the bit timing clock, the first and second local-oscillator signals phase track all communication signals in the transceiver's communication system.
Claims22
A method of providing phase-coherent first and second local-oscillator signals for respective conversion of downstream communication signals to downstream data signals and a corresponding bit data clock and conversion of upstream data signals to upstream communication signals, said method comprising the steps of:
- providing first, second and reference oscillator signals;
- locking the phase of a first frequency-divided sample of said first oscillator signal to the phase of said reference oscillator signal;
- locking the phase of a frequency-divided sample of said second oscillator signal to the phase of said reference oscillator signal;
- and
- locking the phase of a second frequency-divided sample of said first oscillator signal to the phase of a frequency-divided sample of said bit timing clock;
- said first and second oscillator signals thereby converted to said phase-coherent first and second local-oscillator signals.
A local-oscillator system that provides phase-coherent first and second local-oscillator signals for respective conversion of downstream communication signals to downstream data signals and a corresponding bit data clock and conversion of upstream data signals to upstream communication signals, said method comprising the steps of:
- a reference oscillator network that generates a reference clock;
- a first oscillator network that generates said first local-oscillator signal and phase locks a first frequency-divided sample of said first local-oscillator signal to said reference clock;
- and
- a second oscillator network that generates said second local-oscillator signal and phase locks a frequency-divided sample of said second local-oscillator signal to said reference clock;
- wherein said reference oscillator network phase locks a second frequency-divided sample of said first local-oscillator signal to a frequency-divided sample of said bit timing clock.
A communications transceiver that converts downstream communication signals to downstream data signals and a corresponding bit data clock and converts upstream data signals to upstream communication signals, comprising:
- a receiver that has a downconverter mixer and generates downconverted communication signals in response to said downstream communication signals and to a first local-oscillator signal that is applied to said downconverter mixer;
- a demodulator in said receiver that generates said downstream data signals and a corresponding bit timing clock in response to said downconverted communication signals;
- a transmitter having a modulator that generates modulated signals in response to said upstream data signals and wherein said transmitter has an upconverter mixer and generates said upstream communication signals in response to said modulated signals and a second local-oscillator signal that is applied to said upconverter mixer;
- and
- a local-oscillator system that includes:
- a) a reference oscillator network that generates a reference clock;
- b) a first oscillator network that generates said first local-oscillator signal and phase locks a first frequency-divided sample of said first local-oscillator signal to said reference clock;
- and
- c) a second oscillator network that generates said second local-oscillator signal and phase locks a frequency-divided sample of said second local-oscillator signal to said reference clock;
- wherein said reference oscillator network phase locks a second frequency-divided sample of said first local-oscillator signal to a frequency-divided sample of said bit timing clock;
- said first and second local-oscillator signals thereby being phase coherent.
A communications system, comprising:
- a head end that originates and transmits downstream communication signals and receives upstream communication signals;
- a plurality of transceivers that receive said downstream communication signals and transmit said upstream communication signals;
- and
- at least one communication hub that includes at least one transponder that relays said downstream and upstream communication signals between said head end and a respective set of said transceivers;
- wherein each of said transceivers includes:
- a receiver that has a downconverter mixer and generates downconverted communication signals in response to said downstream communication signals and to a first local-oscillator signal that is applied to said downconverter mixer;
- a demodulator in said receiver that generates said downstream data signals and a corresponding bit timing clock in response to said downconverted communication signals;
- a transmitter having a modulator that generates modulated signals in response to said upstream data signals and wherein said transmitter has an upconverter mixer and generates said upstream communication signals in response to said modulated signals and a second local-oscillator signal that is applied to said upconverter mixer;
- and
- a local-oscillator system that includes:
- a) a reference oscillator network that generates a reference clock;
- b) a first oscillator network that generates said first local-oscillator signal and phase locks a first frequency-divided sample of said first local-oscillator signal to said reference clock;
- and
- c) a second oscillator network that generates said second local-oscillator signal and phase locks a frequency-divided sample of said second local-oscillator signal to said reference clock;
- and
- wherein said reference oscillator network phase locks a second frequency-divided sample of said first local-oscillator signal to a frequency-divided sample of said bit timing clock.
Dependencies are inferred from the claim text.