The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 1987
Filed:
Jan. 14, 1985
John F Wakerly, Mountain View, CA (US);
David Systems, Inc., Sunnyvale, CA (US);
Abstract
A clock synchronization system in a digital data switching system, such as a digital PBX. The system has a local clock generating timing signals at a frequency greater than a nominal frequency, a circuit for lowering the local clock frequency and a comparator coupled to a second clock operating substantially at the nominal frequency for activating the lowering circuit so that the local clock is synchronized with the second clock. The system is distributed by placing the local clock and the lowering frequency on the control module of the switching system and placing the comparator to one or more of the line card modules which is receiving the second clock signals. Communication between the comparator and lowering circuit may be over a single line.