Patent ReferencesNRZ Digital data recovery Diskette read data recovery system Clock circuit synchronizer using a frequency synthesizer controlled by a frequency estimator BPSK Costas-type PLL circuit having false lock prevention Patent #: 4713630 InventorsApplicationNo. 07/108371 filed on 10/14/1987US Classes:375/376, Phase locked loop327/159With digital elementExaminersPrimary: Safourek, Benedict V.Attorney, Agent or FirmInternational ClassesH03L 7/08 (20060101)H03L 7/099 (20060101) H03L 7/093 (20060101) AbstractA quotient phase-shift processor is provided which includes novel techniques for realizing phase corrections of a digital phase-locked-loop. A binary phase-detector of the "early-late" type is combined with range-phase-detector circuitry to generate a variable lock acquisition speed. Phase measure and speed control are performed by incremental manipulation which feeds a novel "quotient" processor. The quotient processor integrates the incremental phase errors and performs phase corrections in a nonperiodic fashion, resulting in lower effective proportional loop gain than that provided in standard phase-locked-loops. Wide capture-range and low jitter are obtained by dynamically varying a loop time constant. Pattern dependent noise is reduced by a novel gating technique. High crystal-frequency requirements are reduced, extending the spectral application of digital phase-locked-loops. | |