Data tracking phase locked loop
US4316152A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 24, 1979 |
| Grant date | Feb 16, 1982 |
| Priority date | — |
| Expiry date | Sep 24, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/181
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A counter of modulus n counts the oscillations of a variable frequency oscillator whose center frequency is n-times the nominal frequency of digital data having phase variations. The occurrence of a selected value of the count may be taken as a phase corrected clock for the digital data. Differences between successive values in the counter as pulses of the digital data occur indicate shifts in phase thereof, while the modularity prevents absent data pulses from contributing to the phase error. Successive counts are captured, made available as phase error information in digital form, and used to drive a digital-to-analog converter whose output controls the variable frequency oscillator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.