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:
Oct. 05, 1999
Filed:
Jun. 26, 1997
Paul W Casper, West Melbourne, FL (US);
Marc E Sawyer, Melbourne, FL (US);
Broadband Communications Products, Inc., Melbourne, FL (US);
Abstract
To derive a clock embedded in a digital data stream, a variable data rate synchronizer includes a data rate estimator that derives an estimate of the data rate of data contained in the digital data signal, and a frequency estimator that derives an estimate of the frequency of the output of a voltage controlled oscillator. A phase lock loop includes a phase detector to which the digital data signal and the output of the voltage controlled oscillator are coupled and has an output coupled to a sweepable loop filter. The output of the loop filter is coupled to the voltage controlled oscillator. During an initital frequency acquisition mode, the sweep controller sequentially varies an analog voltage applied to the voltage controlled oscillator, until the estimate of the data rate effectively corresponds to the estimate of the frequency of the output of the voltage controlled oscillator. This terminates the frequency acquisition mode and initiates a phase acquisition mode, during which the sweep controller causes a sawtooth sweep of the loop filter, until the output of the loop filter corresponds to the actual frequency of said embedded clock signal, thereby locking the loop to the embedded clock.