Browse Prior Art Database

Method of Time Coherent Zero Phase Shift CLOCK Generation at Remote Points

IP.com Disclosure Number: IPCOM000036994D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 4 page(s) / 73K

Publishing Venue

IBM

Related People

Hansen, AC: AUTHOR

Abstract

A method is disclosed for the time coherent clock generation at remote points. The method eliminates individual system clock fanout with equal path length to remote points, and it reduces the high frequency requirements of the master clock.

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Method of Time Coherent Zero Phase Shift CLOCK Generation at Remote Points

A method is disclosed for the time coherent clock generation at remote points. The method eliminates individual system clock fanout with equal path length to remote points, and it reduces the high frequency requirements of the master clock.

The system is generally shown in Fig. 1 as a transmission path which provides a master clock signal traveling in opposite directions

(Image Omitted)

at each subsystem node. In an alternate embodiment shown in Fig. 2, the signal is bifurcated and travels along opposite legs of a pair of transmission lines so that the master clock signal travels in opposite directions at each subsystem node.

In Fig. 1, the phase of the clock signals 1 and 2 are coherent, that is, they have zero phase shift, at the node N. The phase shift of the remaining nodes are then shown in the following table: NODE CLOCK 1 CLOCK 2

N 0 0

C -Tn +Tn

B -Tn -T b +T n +T b

A T n -T b -T a +Tn+Tb+Ta

The phase of clock signals 1 and 2 will symmetrically lead and lag the clock signals at node N for all of the nodes. A similar analogy can be stated for Fig. 2 where the signals bifurcated and transmitted to transmission line legs in opposite directions.

A digital phase detector can be used to develop a voltage which is linearly proportional to the phase difference between two signal transitions or edges. Unlike analog phase detectors, the control voltage covers a phase change of +360o .

The conventional use of a phase detector is to esta...