Audio data readout device for motion picture film and clock generating device in motion picture film changeover system
US5608473A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 7, 1995 |
| Grant date | Mar 4, 1997 |
| Priority date | — |
| Expiry date | Mar 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0032
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An audio data readout device for a motion picture film and a clock generating device in a changeover system for a motion picture film. First and second clock generating circuits generate first and second clocks of predetermined frequencies based upon a repetition frequency of perforations detected by first and second film readers and a repetition frequency of a track pitch of audio data, and route the resulting clocks to a changeover switch. At a changeover time, a changeover controller switchingly controls the changeover switch to select the second clock. A system clock generating circuit has loop characteristics of a longer time constant than the first or second clock generating circuits and smoothly locks the second clock to generate a system clock which is outputted. A stable and accurate system clock can be generated and outputted even when film running is unstable at the changeover time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.