Method and apparatus for generating/detecting and address mark
US4746997A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1986 |
| Grant date | May 24, 1988 |
| Priority date | — |
| Expiry date | Feb 10, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An address mark whose pattern is distinguishable from information data is produced by generating a number of relatively long pulses followed by a number of relatively shorter pulses. Preferably, a binary "1" is recirculated through a first predetermined number of stages of a shift register (for a first pre-established number of times) and then through a second (different) predetermined number of stages (for a second pre-established number of times). A signal level transition which defines the beginning or end of a pulse in the address mark pattern is generated in response to each binary "1" output from that shift register. The address mark pattern is detected by, preferably, supplying an input signal to be detected to the same aforementioned shift register, detecting n successive longer pulses and then detecting m successive shorter pulses, where n and m are less than the aforementioned first and second pre-established numbers, respectively. Pulse detection is obtained by sensing binary "0"s in each of successive stages of the shift register.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.