Charge pump for restoring DC in an optical recording read channel
US5355356A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1993 |
| Grant date | Oct 11, 1994 |
| Priority date | — |
| Expiry date | May 19, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/10203
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording system having a DC restored read signal for qualifying pulses in the read channel. The equalized and filtered read signal is input to a differentiator and a DC restore circuit. The zero crossings of the differentiated signal which represent the peaks of the pulses are detected. The DC restore circuit inverts the read signal, generates a reference voltage, and compares the negative pulses peaks of the read signal to the reference voltage. The charge of a capacitor is adjusted according to the difference in voltages of the pulse peaks to that of the reference voltage in order to maintain a constant DC level. The DC restored signal is qualified according to a threshold. Only those pulses which have zero crossings and which have been qualified are considered to be valid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.