High density bias linearized magnetic recording system utilizing Nyquist bandwidth partial response transmission
US4195318A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1978 |
| Grant date | Mar 25, 1980 |
| Priority date | — |
| Expiry date | Mar 20, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/1492
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A digital magnetic recording system is disclosed that utilizes partial response signalling to achieve the Nyquist data pulse rate with minimum bandwidth. A. C. bias is introduced to linearize the magnetic medium which, inter alis, permits reliable multilevel (greater than 2) data storage without impairing data accessibility. Preferably Class IV partial response is utilized with one or more sinusoidal lobes in the data frequency spectrum. The basic binary data to be stored is converted to, for example, ternary and the ternary data is precoded. The precoded ternary data is recorded on the magnetic medium via an interleaved dipulse sequence having a spectral null slightly outside the data frequency band. A pilot tone is inserted at the spectral null for timing recovery and automatic gain control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.