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Wide tracking range, auto ranging, low jitter phase lock loop for swept and fixed frequency systems

United States Patent

October 23, 2001
View the Complete Patent at the US Patent & Trademark Office
Brookhaven National Laboratory - Visit the Office of Technology Commercialization and Partnerships Website
The present invention provides a wide tracking range phase locked loop (PLL) circuit that achieves minimal jitter in a recovered clock signal, regardless of the source of the jitter (i.e. whether it is in the source or the transmission media). The present invention PLL has automatic harmonic lockout detection circuitry via a novel lock and seek control logic in electrical communication with a programmable frequency discriminator and a code balance detector. (The frequency discriminator enables preset of a frequency window of upper and lower frequency limits to derive a programmable range within which signal acquisition is effected. The discriminator works in combination with the code balance detector circuit to minimize the sensitivity of the PLL circuit to random data in the data stream). In addition, the combination of a differential loop integrator with the lock and seek control logic obviates a code preamble and guarantees signal acquisition without harmonic lockup. An adaptive cable equalizer is desirably used in combination with the present invention PLL to recover encoded transmissions containing a clock and/or data. The equalizer automatically adapts to equalize short haul cable lengths of coaxial and twisted pair cables or wires and provides superior jitter performance itself. The combination of the equalizer with the present invention PLL is desirable in that such combination permits the use of short haul wires without significant jitter.
Kerner; Thomas M. (Manorville, NY)
Brookhaven Science Associates (Upton, NY)
09/ 689,976
October 13, 2000
This invention was made with Government support under contract number DE-AC02-98CH10886, awarded by the U.S. Department of Energy. The Government has certain rights in the invention.