Plural phase-lock loops sharing a common frequency control
US5138282A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1990 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Apr 20, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/07
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic tape readback system is disclosed for a multi-track tape player. A single phase lock loop is provided for the channel circuits used for reading signals from the respective tracks on a multi-track tape. A common frequency determining circuit means is coupled to all of the phase lock loops such that the frequency of operation of the phase lock loops is stabilized. A capacitor which has a capacitance usable in the individual phase lock loops for determining a frequency of operation is commonly AC connected to all of the phase lock loops; in this arrangement none of the phase lock loops have the frequency determining capacitor. A capacitance AC couples and DC blocks each of the individual phase lock loops to the frequency determining capacitor such that the individual phase lock loops have their own reference DC levels and yet receive AC input from all of the other phase lock loops.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.