Automatic head tracking system utilizing transducer deflecting means and synchronous demodulation of the envelope signal
US4163994A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1978 |
| Grant date | Aug 7, 1979 |
| Priority date | — |
| Expiry date | Jun 2, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/588
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an apparatus for reproducing video or other information signals recorded in a track on a magnetic tape or other record medium; a magnetic head or transducer is moved along the track for reproducing the information signals recorded therein while a bi-morph leaf which supports the head receives an electrical drive signal for deflecting the head in a direction transverse to that along the track. A deflection responsive signal is generated in correspondence to the deflection of the head from a rest position, for example, in response to varying the capacitance of a capacitor formed of a fixed electrode and a movable electrode on the bi-morph leaf. A control circuit for controlling the deflection of the head includes an oscillator providing a dither oscillation signal which, on application to the bi-morph leaf, causes transverse oscillation of the head about a null position, an envelope detector detecting the envelope of the reproduced output of the head, a multiplier for synchronously demodulating the detected envelope by means of the deflection responsive signal so as to obtain a tracking error signal accurately representative of the deviation of the null position of the head from t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.