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:
Apr. 14, 1992
Filed:
Aug. 11, 1989
Richard L Bennett, Schaumburg, IL (US);
Venkat Narayanan, Boca Raton, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An improved method for detecting that a facility delay has changed is provided. According to the invention, a facility having a delay that may change is coupled to a transmitter and a receiver. The transmitter is coupled to a first clock that transmits a first signal based on its current reading (the first clock signal) from time to time to the receiver via the facility. The receiver is coupled to a second clock that generates a second signal based on its current reading (the second clock signal) responsive to receiving the first clock signal. In operation, the first clock signal is fed downstream (via the facility having the delay), thereby triggering the second clock signal. The two clock signals are then detected and the difference in the two clock readings computed, thereby forming .DELTA..sub.n. The process is then repeated for successive first and second clock signals, thereby forming .DELTA..sub.n+1. The absolute value of .DELTA..sub.n -.DELTA..sub.n+a is then compared with a predetermined value to determine whether the facility time delay has changed. This method is particularly useful in simulcast broadcast systems.