公开(公告)号：US20170373823A1

公开(公告)日：2017-12-28

申请号：US15649078

申请日：2017-07-13

Applicant: Google Inc.

Inventor： Leon Zhou ,  Sheng-Hui Yang

IPC: H04L7/00 ,  H04B10/11 ,  H04L7/033

CPC classification number: H04L7/0075 ,  H04B10/11 ,  H04L7/0016 ,  H04L7/0029 ,  H04L7/0083 ,  H04L7/033 ,  H04L7/0331 ,  H04L7/10

Abstract: A method includes receiving an optical signal through an optical link and determining a receiving power for the optical link. The method further includes comparing the receiving power for the optical link to a first receiving power threshold and transitioning a clock and data recovery circuit form a normal mode to a holdover mode when the receiving power is less than the first receiving power threshold. The clock and data recovery circuit, when operating in the holdover mode, configured to hold a recovered clock to a known-good clock frequency. When the receiving power for the optical link is greater than a second receiving power threshold, the method initiates a transition of the clock and data recovery circuit from the holdover mode to the normal mode and reacquires synchronization between the recovered clock and a current rate of the incoming data stream using the known-good clock frequency.

公开(公告)号：US09749123B1

公开(公告)日：2017-08-29

申请号：US15176984

申请日：2016-06-08

Applicant: Google Inc.

Inventor： Leon Zhou ,  Sheng-Hui Yang

IPC: H04B10/11 ,  H04L7/00 ,  H04L7/033

CPC classification number: H04L7/0075 ,  H04B10/11 ,  H04L7/0016 ,  H04L7/0029 ,  H04L7/0083 ,  H04L7/033 ,  H04L7/0331 ,  H04L7/10

Abstract: A method includes receiving an optical signal through an optical link and determining a receiving power for the optical link. The method further includes comparing the receiving power for the optical link to a first receiving power threshold and transitioning a clock and data recovery circuit form a normal mode to a holdover mode when the receiving power is less than the first receiving power threshold. The clock and data recovery circuit, when operating in the holdover mode, configured to hold a recovered clock to a known-good clock frequency. When the receiving power for the optical link is greater than a second receiving power threshold, the method initiates a transition of the clock and data recovery circuit from the holdover mode to the normal mode and reacquires synchronization between the recovered clock and a current rate of the incoming data stream using the known-good clock frequency.