PLL circuit and optical communication reception apparatus

Details PLL circuit and optical communication reception apparatus PLL circuit and optical communication reception apparatus

2005-07-05

2005-07-05

Pascal, Leslie (Department: 2633)

Optical communications

Transmitter

Having particular modulation

C398S150000, C398S154000, C398S155000

Reexamination Certificate

active

06915081

ABSTRACT:
The invention provides a PLL circuit wherein, even if the duty ratio of an input signal varies, stabilized PLL operation is achieved. The PLL circuit includes a phase detection circuit and a frequency detection circuit. The frequency detection circuit includes a pair of D-type flip-flops for sampling first and second clock signals having different phases from each other in synchronism with an input signal at each rising or falling changing point of the input signal for each period, and a control logic circuit for logically operating the signals sampled by the D-type flip-flops and the signals sampled successively subsequently by the D-type flip-flops. The control logic circuit generates an UP pulse signal or a DOWN pulse signal based on a result of the arithmetic operation.

REFERENCES:
patent: 5727019 (1998-03-01), Tatsumi
patent: 5889828 (1999-03-01), Miyashita et al.
patent: 6081572 (2000-06-01), Filip
patent: 6333678 (2001-12-01), Brown et al.
patent: 6353358 (2002-03-01), Yoshie
patent: 6556086 (2003-04-01), Keaveney et al.
Hui Wang and Richard Nottenburg: XP-000862367; A 1Gb/s CMOS Clock and Data Recovery Circuit; dated Feb. 1999, vol.42, pp. 354-355.
Hui Wang and Richard Nottenburg: A CMOS Low-jitter Phase Frequency Detector for Giga-bit/s Clock Recovery; dated Jul. 1999; pp. 91-93.
T.H. Toifl and P. Moreira: Simple frequency detect or circuit for biphase and NRZ clock recovery: dated Oct. 1, 1998 vol. 34, No. 20; pp. 1922-1923.

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