Variable delay oscillator buffer

Details Variable delay oscillator buffer Variable delay oscillator buffer

2011-07-19

2011-07-19

Fan, Chieh M (Department: 2611)

Pulse or digital communications

Synchronizers

Phase displacement, slip or jitter correction

Reexamination Certificate

active

07983375

ABSTRACT:
A novel and useful variable delay digitally controlled crystal oscillator (DCXO) buffer (i.e. slicer). A conventional slicer following the DCXO is modified to introduce a controlled random variable delay into the buffered DCXO clock. The resultant output clock signal is then used as input to the TDC of an ADPLL circuit to alleviate the subharmonic mixing based deterioration caused by LO/TX coupling through the crystal pins, and to alleviate the dead-beat effects caused by the finite resolution of the TDC. Two mechanisms for introducing variable delay into the buffered DCXO output clock signal are presented: a first mechanism that creates variable delay in fine steps and a second mechanism that creates variable delay in coarse steps. In both mechanisms, switches are incorporated into the slicer circuitry and controlled using digital bit sequences which may comprise dithering signals. The switches are turned on and off via the digital bit sequences which varies the delay of the slicer clock output which serves to shift the rising and falling transition points of the resultant output clock signal. The jitter is shifted to higher frequencies where it is filtered out by the PLL loop filter.

REFERENCES:
patent: 6809598 (2004-10-01), Staszewski et al.
patent: 2006/0033582 (2006-02-01), Staszewski et al.
patent: 2006/0038710 (2006-02-01), Staszewski et al.
patent: 2006/0208779 (2006-09-01), Lin et al.
patent: 2006/0226881 (2006-10-01), Jaussi et al.
U.S. Appl. No. 11/853,182, filed Sep. 2007, Sheba et al.
U.S. Appl. No. 11/832,292, filed Aug. 2007, Entezari et al.

Affiliated with

Also associated with

Rating

Variable delay oscillator buffer does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Variable delay oscillator buffer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable delay oscillator buffer will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2686768