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A New Phase Detector Scheme for Reducing Jitter in Clock Recovery Circuits
Kang-Yoon LEE Deog-Kyoon JEONG
IEICE TRANSACTIONS on Electronics
Publication Date: 2003/02/01
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
phase detector, jitter, clock recovery, PLL,
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A simple phase detector reducing the pattern dependent jitter in clock recovery circuit is developed in this paper. The developed phase detector automatically aligns the recovered to clock in the center of the data eye, while producing no ripple to the control voltage in locked condition of the PLL based clock recovery circuit. The UP and DOWN signals are separately generated to align them in locked condition. Thus, no explicit transient waveforms do not exist at the output of the phase detector. The elimination of high frequency ripple improves the jitter characteristics of the clock recovery circuit. The delay unit used in our phase detector requires no accurate control of the delay time. This feature eliminates the use of DLL to generate the precise delay time, which reduce the power consumption and area of the phase detector. The simulation shows that the RMS timing jitter is reduced by more than four times when compared with the conventional scheme. The rms jitter is 32 ps for the proposed phase detector and 133 ps for the phase detector in conventional scheme. In conventional scheme, even when the lock is achieved, the phase detector produces a triwave transient on the control voltage of the VCO, which depends on the data pattern. In the proposed phase detector, no such transient waveforms do not exist. The proposed phase detector can be incorporated in high performance clock recovery circuit for data communication systems.