Retrieving data recorded at different bit densities
US5737141A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1996 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | Aug 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/00891
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A Digital Data Storage (DDS) data storage mechanism for reading DDS tapes containing data at either 61 kbpi or 122 kbpi has two circuits for recovering data from signals induced in a magnetic head by magnetic patterns on the tape. One circuit incorporates a clipping amplifier, a phase-locked loop (PLL), and a latch to sample the two-level signal obtained at 61 kbpi, at times defined by clock pulses from the PLL. The second circuit incorporates a PR-1 partial-response maximum-likelihood (PRML) detector to decode the three-level signal obtained at 122 kbpi. The cosine frequency response characteristic of the PR-1 channel facilitates use of the same rotary head drum and magnetic head gap for reading tapes at either bit density.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.