Automatic head height control apparatus
AssigneeSony Corporation
InventorsMasayuki Takano, Sadao Hosoi, Yuichi Matsushita
Life of this patent
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Abstract
In a video tape recorder which employs a rotary magnetic head secured on a deflectable device, such as a bi-morph leaf, to dynamically perform head tracking during reproduction of previously recorded tracks regardless of the tape transport speed; the height of the magnetic head is detected during recording to produce a feedback control signal which electrically adjusts the height of the magnetic head by deforming the bi-morph leaf to overcome hysteresis deflection of the bi-morph leaf so that the magnetic head is returned to and maintained at a normal height during recording.
Claims13
A head height control apparatus for at least one magnetic head movable in a closed path during selective operations in recording and playback modes and being mounted on an electrically deflectable element for displacement in a direction transversely of of said path, comprising:
- sensing means periodically disposed in facing relation to said head for achieving a transducing relation therebetween and being operative in said recording mode of the head for producing at least one detected signal in response to said transducing relation, which signal contains information in respect to a magnitude and a direction of deviation of any deviation of said at least one magnetic head from a predetermined height in said direction transversely of the path;
- and
- control means responsive to said at least one detected signal for electrically deflecting and electrically deflectable element in opposition to said direction of deviation and in an amount tending to compensate for said deviation and thereby maintain said at least one magnetic head at said predetermined height when in said recording mode.
A head height control apparatus for a video tape recorder of the type having a drum at least a portion of which is rotatable about a central axis, at least a first electrically deflectable element having a first end affixed to said portion of the drum and a second end which is free, and a magnetic head affixed to said second end for movement therewith in a circular path and for displacement in a direction transversely of said path upon deflection of said element, said magnetic head having a normal height in said direction, comprising:
- at least a second magnetic head at a fixed location adjacent said path which has a predetermined relationship to said normal height and at which said second magnetic head is periodically in transducing relation with the first mentioned magnetic head on each circuit by the latter of said path;
- means connected with said second magnetic head for producing a detected signal in response to each periodic transducing relationship of said first magnetic head with said second magnetic head, said detected signal containing information about at least a direction of any deviation of said first magnetic head from said normal height;
- and for applying a control signal to said electrically deflectable element which is effective to displace said first magnetic head toward said normal height and thereby eliminate said deviation.
Dependencies are inferred from the claim text.