Ciena Corporation
Highly linear phase rotators with continuous rotation

Abstract:

Described herein are apparatus and methods for highly linear phase rotators with continuous rotation. A method includes generating a first code and a second code based on a desired offset to match a first and second frequency, respectively, calibrating the first code and the second code based on first phase rotator characteristics and second phase rotator characteristics, respectively, generating first N phase offset codes and second N phase offset codes from a calibrated first and second code, respectively, wherein each phase offset code constrains functionality of the first phase rotator and the second phase rotator, respectively, associated with a phase of the input clock to a defined region of operation, rotating a clock using the first N phase offset codes and the second N phase offset codes to match the first and second frequency, respectively.