Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
2006-08-09
2010-06-22
Le, Lana N (Department: 2614)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S255000, C455S265000, C455S313000
Reexamination Certificate
active
07742785
ABSTRACT:
Techniques for generating reference signals for multiple communication systems are described. An apparatus comprises a reference oscillator, a frequency control unit, and a plurality of frequency synthesizers. The reference oscillator generates a main reference signal and may be a crystal oscillator or some other type of oscillator. The frequency control unit estimates the frequency error of the main reference signal and provides a frequency error estimate. The plurality of frequency synthesizers receive the main reference signal and generate a plurality of system reference signals for a plurality of systems. At least one (e.g., each) frequency synthesizer corrects the frequency error of the main reference signal based on the frequency error estimate from the frequency control unit. Each frequency synthesizer may include a sigma-delta modulator used to generate a divider control for a phase locked loop (PLL). The divider control corrects for the frequency error of the main reference signal.
REFERENCES:
patent: 5465402 (1995-11-01), Ono et al.
patent: 5603109 (1997-02-01), Feeney
patent: 5604468 (1997-02-01), Gillig
patent: 5815042 (1998-09-01), Chow et al.
patent: 6307441 (2001-10-01), Sharpe
patent: 6335953 (2002-01-01), Sanderford et al.
patent: 6876874 (2005-04-01), Arnaud et al.
patent: 7113751 (2006-09-01), Barak
patent: 7205850 (2007-04-01), Uozumi et al.
patent: 7239857 (2007-07-01), Abraham
patent: 7486145 (2009-02-01), Floyd et al.
patent: 7498986 (2009-03-01), Thomas
patent: 2004/0183601 (2004-09-01), Zhang
patent: 2005/0079846 (2005-04-01), Sendonaris et al.
patent: 2006/0111141 (2006-05-01), Smith et al.
patent: 2006/0121864 (2006-06-01), Rodgers et al.
patent: 2008/0129600 (2008-06-01), Thomas
patent: 1206039 (2002-05-01), None
patent: 1213830 (2002-06-01), None
patent: 1467518 (2004-10-01), None
patent: 2004091231 (2004-10-01), None
Scott Meninger, “Sigma-Delta Fractional-N Frequency Synthesis,” MIT, Jun. 7, 2004.
De Muer and Steyaert, “On the Analysis of Delta Sigma Fractional-N Frequency Synthesizers for High-Spectral Purity,” IEEE Transactions on Circuits and Systems, Nov. 2003.
Riley, Copeland and Kwasniewski, “Delta-Sigma Modulation in Fractional-N Frequency Synthesis”, IEEE Journal of Circuits and Systems, May 1993.
Roermund, et al., “Analog Circuit Design: Fractional-N Synthesizers, Design for Robustness, Line and Bus Drivers,” Jan. 1, 2003, Kluwer, paragraph 4.1.3.
International Search Report—PCT/US07/075328, International Search Authority—European Patent Office, Sep. 15, 2008.
Written Opinion—PCT/US07/075328, International Search Authority—European Patent Office, Sep. 15, 2008.
Le Lana N
QUALCOMM Incorporated
Xu Jiayu
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