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:
Jan. 09, 1996
Filed:
Sep. 30, 1993
James R Bortolini, Boulder, CO (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
Simplifying measurement equipment so that any two frequency sources can be accurately and quantitatively compared to each other. With this simplified measurement equipment, calibration can be performed on an oscillator using an external reference signal, while the oscillator is being used in an active system. By simplifying the measurement equipment, the equipment can be built into a time base unit allowing recalibration to be performed at relatively short time intervals. A frequency difference detector based on ring counters and an existing controller in a telecommunication switching system compare an accurate external reference against an oscillator of the time base unit for calibration in the field. Within the telecommunication switching system, a highly accurate external reference signal is normally available from an interconnected telecommunication network. The use of ring counters in the frequency difference detector allows for simple measurement equipment which adds little to the cost of the time base unit. Further, since measurement equipment is all digital, no tuning of the equipment is necessary as is required of measurement equipment having analog components.