# US 4,393,416 A · Tracking system for a videotape recorder

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- Number: US 4,393,416 A
- Document ID: US4393416A
- Status: Granted
- Kind: A
- Application number: 06/281,043
- Filed: 1981-07-07
- Granted: 1983-07-12
- Earliest claimed: 1980-07-09
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Akihiro Takeuchi; Masaaki Kobayashi; Kiyoji Fujisawa
- Web page: https://patentgrep.com/patent/US4393416A

## CPC

- G11B 5/584: for track following on tapes
- G11B 5/588: by controlling the position of the rotating heads (by controlling the speed of the record carrier G11B15/467; by controlling speed of the heads G11B15/473; {by moving the transducing part of the head relative to the headwheel, in the direction of the scanning movement G11B15/1841})
- G11B 5/592: using bimorph elements supporting the heads
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

A tracking system of the present invention comprises positionable elements, rotary video heads mounted on the positionable elements, a control head, a frequency generator attached to a capstan motor, and a displacing pattern generator. The displacing pattern generator includes counters which count the pulses from the frequency generator and are reset by control signals reproduced by the control head, a still pattern generator, and an adding means which adds the output signal from the counter and the output signal from the still pattern generator. The output signal of the displacing pattern generator is amplified and applied to the positionable elements. As result, the video heads mounted on the positionable elements can properly trace on a recorded video track at both a normal tape speed or at another tape speed.

## Claims

### Claim 1

A tracking system for a video recorder/reproducer employing a record medium having tracks for recording video signals and control signals which are representative of the record position of said video signals, said system comprising:
a transducing means for reproducing video signals recorded along said track on said record medium;
a positionable means with said transducing means mounted at a location thereon, said positionable means being movable at said location for displacing position of said transducing means;
a control signal reproducing means for reproducing said control signals recorded along said track on said record medium;
a means for dividing interval of said control signals, said dividing means developing sub-control signals whose number is representative of the transported length of said record medium;
a rotation phase detector for detecting the rotating phase of said transducing means and for providing an output signal corresponding thereto;
an operational means for developing a displacement pattern signal which is representative of the location of said video track recorded on said record medium relative to said transducing means by using said control signals, said sub-control signals, and said output signal from said rotating phase detector; and
a means for supplying said displacement pattern signal to said positionable means, wherein said operational means comprises: (1) a still pattern generator for developing a still pattern signal whose value is zero at a beginning of scanning of said transducing means and whose value corresponds to one track pitch at an end of scanning of said transducing means, (2) a counter unit for counting said sub-control signals and for generating bias signals and (3) an adder which adds the output signals of said still pattern generator and the output of said counter developing said displacing pattern signal; and wherein
said counter unit comprises: (1) a first counter which is reset by said control signals and counts said sub-control signals, (2) a second counter which is preset to a predetermined value m when an output signal of said first counter becomes larger than m and which counts said sub-control signals, and (3) a third counter comprising two separate counters, each of which is preset to an output signal of said second counter at a predetermined time and which counts said sub-control signals, outputs of said third counter comprising two separate counters being applied to said adder, whereby said transducing means is capable of tracking properly on said recorded video track at an arbitrary transporting speed of said record medium.

### Claim 2 (depends on 1)

A tracking system as claimed in claim 1, wherein said dividing means comprises: a rotary disk which rotates with running of said record medium, and a pulse generator which develops pulse signals in proportion to the rotating angle of said rotary disk.

### Claim 3 (depends on 1)

A tracking system as claimed in claim 1, wherein said control signal reproducing means comprises a magnetic head which responds to magnetic flux.