Read signal detection in ternary 3PM magnetic recording
US4544963A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 1984 |
| Grant date | Oct 1, 1985 |
| Priority date | — |
| Expiry date | Jan 16, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/1488
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Circuitry for distinguishing each value in a read signal magnetically recorded in ternary-3 position modulation in which the values 1, 2 and 0 are detected and equalized into a singlet, a doublet and absence of magnetic flux change. The circuitry first determines the position locations of each singlet peak and doublet crossover point to establish proper timing of the output signals and then identifies the particular type of signal appearing at the timing points in the read signal sequence. Singlets are identified by the much greater amplitudes in the integrated read signal. Doublets are identified as waveforms having slopes at zero crossovers that correspond in polarity to that of the previous singlet. A novel detector circuit is provided that can correctly identify doublets in a code sequence, irrespective of the presence of a previous singlet, when a recording rule is followed that includes the insertion of a number of consecutive ternary 0 symbols into the recorded signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.