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:
Aug. 14, 1990
Filed:
Sep. 01, 1989
Jeffrey P Viola, Brookhaven, PA (US);
General Electric Company, Camden, NJ (US);
Abstract
In a burst mode fiber-optic transmitter-receiver or bus interface unit (BIU), the clock recovery process by a phase lock loop (PLL), or more generally a servo loop, detects the frequency difference between the PLL oscillator and the transmitter oscillator, and generates a control voltage which is combined with the voltage controlled oscillator (VCO) error voltage to urge the PLL oscillator towards the transmitter's frequency. An activity detector detects the presence of received signal, and 'freezes' or holds the control voltage to the PLL so the PLL is free to slew to the frequency and phase of the clock of the received burst. Thus, the PLL is maintained near the expected frequency of the received clock signal for fast acquisition. After the burst, the activity detector once again allows the frequency control signal to assert command of the VCO frequency.