Endless magnetic tape video recorder/player with head centering means

• US 4,321,634 A
• Filed: 05/05/1980
• Issued: 03/23/1982
• Est. Priority Date: 10/07/1977
• Status: Expired due to Term

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Lehureau, Jean-Claude
• Primary Examiner(s): Moffitt, James W.
• Assistant Examiner(s): Faber, Alan
• Application Number:
  US06/146,412
• Time in Patent Office: 687 Days
• Field of Search: 360/21, 360/22, 360/23, 360/33, 360/70, 360/75, 360/77, 360/83, 360/107, 360/109, 360/121, 360/88
• US Class Current: 360/70
• CPC Class Codes: G11B 15/1891 the record carrier being endless
• CPC Class Codes: G11B 5/00817 on longitudinal tracks only, e.g. for serpentine format recording
• CPC Class Codes: G11B 5/0083 for parallel information processing, e.g. PCM recording
• CPC Class Codes: G11B 5/4893 relative to moving tape
• CPC Class Codes: G11B 5/52 with simultaneous movement of head and record carrier, e.g. rotation of head G11B5/588 takes precedence
• CPC Class Codes: G11B 5/584 for track following on tapes

Abstract

A device for recording and playing back information comprising an endless tape whereof one part has a translational movement in a direction x and n magnetic heads integral with one another whereof the gaps face that part and are aligned in a transverse direction y. The heads have a slow movement in the direction y and form n continuous tracks forming parallel and equidistant portions in the direction y.

Claims

1. A video tape recording and playback device comprising an endless magnetic tape, magnetic head means having at least two gaps stacked across the width of said tape, tape driving means for continuously moving said tape past said magnetic head means, and head moving means for laterally moving said magnetic head means in a direction perpendicular to the direction of transport of said tape;

said gaps having axes angularly offset by equal positive and negative values in relation to said direction;

said gaps recording along said tape a timing signal on two equally spaced tracks;

said magnetic head means supplying two playback signals upon reading out said tracks with two gaps in azimutal alignment with said gaps;

phase comparator means being provided for supplying in response to said playback signal a control voltage corresponding to the phase shift between said playback signals;

said control voltage being fed back to a control input of said head moving means for cancelling out at playback any lateral offset of said gaps in relation with said tracks.

2. A device as claimed in claim 1, wherein said head means includes at least n magnetic heads, n being an integer at least equal to 2;

said n heads being integral with one another;

the centres of the gaps of said heads being aligned in said direction y;

said gaps following n continuous tracks forming, in said direction y, parallel portions of tracks having a pitch h.

3. A device as claimed in claim 2, wherein the distance between the centres of two adjacent gaps is equal to h;

the distance traversed by each of said heads in said direction y during the unwinding of the total length of said tape being equal to n×

h.

4. A device as claimed in claim 2, wherein the distance between the centre of two adjacent gaps is equal to h₁ greater than h;

the distances traversed by each of said heads in said direction y during the unwinding of the total length of said tape being equal to h;

the width of said tape in said direction y being greater than or equal to n×

h₁.

5. A playback device as claimed in claim 4, wherein said timing signal comprises two series of synchronizing pulses synchronously recorded at the same time as said information with a fixed frequency f_o.

6. A device as claimed in claim 1, enabling an information signal having a pass-band B to be recorded by n magnetic recording heads in the form of n tracks on a magnetic tape so as to be able to be read out by scanning of said tracks by n magnetic playback heads, said recording device further comprising coding means for splitting up said signal into n electrical recording signals having a pass-band less than B;

the two terminals of said n recording heads being simultaneously and respectively supplied by said n recording signals.