Speed-switchable readback signal equalization and direct-current restoration
US4093965A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 16, 1976 |
| Grant date | Jun 6, 1978 |
| Priority date | — |
| Expiry date | Aug 16, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/035
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus for recovering signals read back from a recording medium at different relative recording medium speeds have speed-switchable equipment for equalizing readback signals over frequency bands having different peak to-bandedge roll-off regions for different relative recording medium speeds. High-frequency equalization means in the speed-switchable equipment equalize readback signals in the peak-to-bandedge roll-off regions by providing speed-switchable frequency peaking characteristics and speed-switchable cut-off frequency characteristics and in company with each other shift the frequency peaking characteristics and cut-off frequency characteristics to the different peak-to-bandedge roll-off regions for different relative recording medium speeds. Methods and apparatus for direct-current restoration of an alternating signal provide a first signal analogous to the alternating signal and asymmetrical in a first sense relative to a reference voltage, and a second signal analogous to the alternating signal and asymmetrical in a second sense relative to a reference voltage. These first and second signals are combined and disposed symetrically about a direct-current reference voltag…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.