Method and apparatus for recording and reproducing video

Abstract

Abstract The video or television signals are broken into numerous elements representing spaced portions of the video display screen along the line sweep, and imprints (electrical or optical) for each element are made in a path on a rotating medium which may be a disc, drum or belt. The lineal length of each imprint on the path is determined by the light characteristic of the video signal being recorded. Clock marks are permanently recorded in a separate path on the rotating medium, one for each spacing of the line elements, to accurately locate the elements on the rotating medium and thereby accurately locating the elements on the screen when the information is decoded. For the U.S. television operational mode, one rotation of the rotating medium takes place in one thirtieth of a second to give a complete picture frame, including interlacing. Maximum density of imprints is achieved by using an extremely narrow width of about one ten thousandth to one thousandth of an inch wide, and not only make adjacent tracks contiguous but actually overlapping. This is accomplished by a highly efficient transducer in contact with the recording medium and to prevent this razor edge transducer from cutting the recording medium, a body surrounds the transducer structure to give a non-cutting bearing force per unit of area. With such narrow tracks, extreme accuracy of concentricity is required of the spindles on which the rotating medium moves and of the mounting of the medium on the spindles. The invention provides structure and a method of machining spindles that gives this extreme accuracy of concentricity. Sound is supplied by using an unused portion of the video signal and the trailing edges of the line start pulses are convenient portions. Because the tracks may overlap or small errors in concentricity may occur that would otherwise meld together sound from two side-by-side tracks, only certain digitally spaced parts of one track are used for sound and different digitally spaced portions of another track are used. For example, every fourth line start pulse can be used on one track and the used pulses on the succeeding track are staggered with respect to the one track, and so on. The method and apparatus permits transcribing broadcast television signals or transcribing directly from a television set and permits playback directly into a set, or if modulated by very high or ultra high frequency waves, may be broadcast as conventional television, or introduced directly into a broadcast television receiver by attachment to the antenna terminals.

Inventors

• 👤 George E Zenzefilis

Bibliographic Details