Patent ID: 7697647
Filing Date: 2010-04-13
Classification: H03L

Abstract:
1. A clock synchronization device, comprising: a plurality of phase detectors, each phase detector receiving corresponding reference clock signals input from one of a plurality of reference clock signals; for each of the phase detectors there are: (a) an associated first register for receiving from the respective phase detector, a corresponding phase difference between a phase of the corresponding reference clock signals and a phase of timing signals from a computational system when the corresponding reference clock signals are used for determining the phase of the timing signals; and (b) an associated second data register for storing data of a phase difference between the phase of the corresponding reference clock signals and the phase of the timing signals when the corresponding reference clock signals are not used for determining the phase of the timing signals; wherein for a designated one of the reference clock signals used for determining the phase of the timing signals, the designated one of the reference clock signals is received by a first phase detector (PD wherein for an alternative one of the reference clock signals received by a second phase detector (PD circuitry for obtaining a correction in the phase of the timing signals between the phase of the designated one of the reference clock signals and the phase of the timing signals, wherein the circuitry combines: (c) the first value, and (d) an instance of the data from the associated second data register for PD a clock selector for selecting between at least the designated one of the reference clock signals and the alternative one of the reference clock signals, wherein, when the clock selector signals a switch from selecting the designated one of the reference signals to the alternative one of the reference clock signals, (e) and (f) following occur: (e) PD (f) the circuitry combines: (i) the third value, and (ii) an instance of the data from the associated second data register for PD