Versatile phase-locked loop for read data recovery
US3944940A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 6, 1974 |
| Grant date | Mar 16, 1976 |
| Priority date | — |
| Expiry date | Sep 6, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A clock pulse generating system is disclosed for recovery of read data from magnetic record media comprised of a phase-locked loop for tracking data pulses. The loop employs simple digital logic gates for phase error detection, third-order filtering for the transient phase and frequency error reduction and a voltage controlled oscillator (VCO) comprised of a capacitor charged by current from a voltage controlled current source, voltage threshold detection means, and means responsive to the threshold detection means to quickly discharge the capacitor. The VCO includes a flip-flop at its output to produce a square-wave feedback signal to the phase detection gates and to a data recovery circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.