Claims
- 1. A communication system comprising:
a base station, said base station having a base station clock circuit having as an output a base station clock signal comprising base station timing information, said base station clock signal forming an input to a base station radio, said base station radio including circuitry for repetitive transmission of information based upon said base station timing information; a mobile station, said mobile station comprising a mobile station radio for repetitively receiving said transmitted information, said mobile station comprising a radio interface module having as one of its inputs said repetitively transmitted information, said radio interface module comprising circuitry for deriving said base station timing information from said transmitted information, said radio interface module having as an output a timing signal indicative of said base station timing information, said timing signal forming an input to a mobile station clock circuit; said mobile station clock circuit comprising circuitry for generating a mobile station clock signal based upon said base station timing information and circuitry for updating said mobile station clock signal upon receipt of said repetitive transmissions.
- 2. The communication network of claim 1, said base station timing information comprising a preamble.
- 3. The communication network of claim 1, wherein said circuitry for deriving said base station timing information from said transmitted information comprises a digital matched filter circuit which produces a matched filter detect pulse indicative of the base station timing information.
- 4. The communication network of claim 1, wherein said mobile station clock circuit comprises an adjustable oscillator circuit.
- 5. The communication network of claim 4, wherein the frequency of said mobile station clock signal varies according to a change in a voltage applied across said adjustable oscillator circuit.
- 6. The communication network of claim 4, wherein said mobile station clock circuit comprise a varactor tuning circuit which applies a variable voltage across said adjustable oscillator circuit.
- 7. The communication network of claim 4, wherein said circuitry for generating a mobile station clock signal based upon said base station timing information and circuitry for updating said mobile station clock signal upon receipt of said repetitive transmissions comprises
a first dividing circuit for deriving a first lower frequency component square wave signal from said mobile station clock signal, a second dividing circuit for deriving a second lower frequency component square wave signal from said base station timing information, and an XOR circuit for comparing said first and second lower frequency component square wave signals and generating a corresponding comparison output signal which is input to said variable oscillator circuit.
- 8. The communication network of claim 7, further comprising a varactor tuning circuit which applies a voltage across said adjustable oscillator circuit directly proportional to said comparison output signal.
- 9. The communication network of claim 1, further comprising a base station controller, said base station controller includes as one input said base station clock signal and outputs timing information to said radio based upon said base station clock signal.
- 10. The communication network of claim 1, wherein said circuitry for deriving said base station timing information from said transmitted information, comprises a digital matched filter having said received transmissions as an input and having as an output a timing pulse indicative of said base station timing information, an early/late detector having as an input timing pulse and having as an output a timing adjustment signal, a pulse width modulator having as an input said timing adjustment signal and having as an output said timing signal which comprises a pulse width modulated signal.
- 11. A communication network, comprising:
a base station, said base station having
an adjustable base station oscillator circuit outputting a base station clock signal, means for adjusting said base station oscillator circuit, and means for transmitting said base station clock signal; and a mobile station, said mobile station having means for receiving said base station clock signal, an adjustable mobile station oscillator circuit outputting a mobile station clock signal, means for comparing said mobile station clock signal to said base station clock signal and for generating a corresponding base station clock comparison output signal, and means for adjusting said mobile station oscillator circuit based on said base station clock comparison output signal.
- 12. The communication network of claim 11, said base station further comprising means for generating a reference clock signal derived from an reference network, wherein said reference clock signal has a frequency which is a lower frequency component of said base station clock signal frequency.
- 13. The communication network of claim 12, said base station further comprising
a first dividing circuit for deriving a lower frequency component signal from said base station clock signal, means for comparing said lower frequency component signal with said reference clock signal and generating a corresponding reference signal comparison output signal.
- 14. The communication network of claim 13, wherein said means for adjusting said base station oscillator circuit comprise a varactor tuning circuit which supplies a voltage across said oscillator circuit directly proportional to said reference signal comparison output signal.
- 15. The communication network of claim 13, wherein said lower frequency component signal comprises a first square wave, said reference clock signal comprises a second square wave, and said means for comparing said lower frequency component signal to said reference clock signal comprise an XOR circuit.
- 16. The communication network of claim 12, wherein said reference clock signal is derived from a public switched telephone network.
- 17. The communication network of claim 12, wherein said base station adjustable oscillator circuit comprises a voltage sensitive 20 MHZ crystal and said reference clock signal comprises a 4 KHz square wave derived from an 8 KHz analog signal supplied by a public switched telephone network.
- 18. The communication network of claim 11, said mobile station further comprising means for generating a vocoder clock signal, wherein said mobile station clock signal and said vocoder clock signal each comprise a multiple of a common lower frequency component signal.
- 19. The communication network of claim 18, wherein said means for generating said vocoder clock signal comprise an adjustable vocoder timing oscillator circuit.
- 20. The communication network of claim 19, said mobile station further comprising
means for deriving a first lower frequency component signal from said mobile station clock signal, means for deriving a second lower frequency component signal from said vocoder clock signal, and means for comparing said first and second lower frequency component signals and generating a corresponding mobile station clock comparison output signal.
- 21. A method of synchronizing a base station and a remote station in a communication network, comprising the steps of:
generating timing information at the base station; transmitting said timing information from the base station to the mobile station; generating a clock signal at the mobile station; comparing said timing information and said clock signals at said mobile station; and adjusting said clock signal to match said timing information.
- 22. The method of synchronizing of claim 21, comprising the additional steps of:
comparing said timing information with a reference clock signal derived from a reference network; and adjusting said timing information to match said reference clock signal.
- 23. The method of synchronizing of claim 21, comprising the additional steps of:
receiving periodic GPS pulse signals at the base station; and resetting a signal frame transmission cycle derived from said timing information upon receipt of a GPS pulse signal.
- 24. A method of synchronizing communication signals sent between a base station and a mobile station in a communication network, comprising the steps of:
generating a first clock signal at the base station; comparing said first clock signal with a reference clock signal derived from a reference network; adjusting said first clock signal to match said reference clock signal; transmitting a signal to said base station from which the adjusted first clock signal can be derived; deriving said adjusted clock signal at the remote station generating a second clock signal at the remote station; comparing said first and second clock signals; adjusting said second clock signal to match said derived adjusted first clock signal; receiving periodic GPS pulse signals at the base station; and resetting a signal frame transmission cycle derived from said first clock signal upon receipt of a GPS pulse signal.
- 25. The method of synchronizing communication signals of claim 24, wherein the signal transmitted is in the form of a non-data carrying preamble of a communication signal; and
wherein the adjusted first clock signal is derived by detecting said preamble at the remote station with a digital matched filter circuit which produces a matched filter detect pulse.
- 26. A method of synchronizing communication signals sent between stations of a communication network, comprising the steps of:
generating a first clock signal at a first station; operating communication circuitry at said first station according to a first station frame transfer cycle matching said first clock signal; comparing said first clock signal with a reference clock signal derived from a reference network; adjusting said first clock signal to match said reference clock signal; generating a second clock signal a second station; operating communication circuitry at said second station according to a second station frame transfer cycle matching said second clock signal; comparing said first and second clock signals; and adjusting said second clock signal to match said first clock signal.
- 27. The method of synchronizing communication signals of claim 26, comprising the additional steps of:
receiving periodic GPS pulse signals at the first station; and resetting said first station frame transfer cycle upon receipt of a GPS pulse signal.
RELATED APPLICATION
[0001] This application is a continuation of and claims priority to U.S. patent application Ser. No. 08/749,105, which is incorporated herein by reference in its entirety.
Continuations (1)
|
Number |
Date |
Country |
Parent |
08749105 |
Nov 1996 |
US |
Child |
09838006 |
Apr 2001 |
US |