Automatic head tracking system
US4172265A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1978 |
| Grant date | Oct 23, 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 signal is generated in correspondence to the deflection of the head from a rest position by a circuit which includes a strain gauge fixed 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 signal so as to obtain a tracking error signal accurately representative of the deviation of the null position of the head from the center of the track, and an adder adding the tracking error signal to the dither oscillati…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.