Magnetic video head position control

Claim 2

Apparatus for controlling the position of a positionable magnetic head, said apparatus comprising: a positionable magnetic head; means for applying a constant potential to said positionable magnetic head so that the positionable magnetic head is rigidly held in a fixed position; means for comparing said constant potential with a predefined voltage; and, means for producing an output if said constant potential differs from said predefined voltage.

Claim 3

Apparatus as defined in claim 1, wherein said means for producing an output further comprises means for signaling said constant potential differs from said predefined voltage.

Claim 4

Apparatus as defined in claim 1, wherein said means for producing an output further comprises means responsive to a difference between said constant potential and said predefined voltage, for adjusting said constant potential to a value equal to said predefined voltage.

Claim 5

Apparatus as defined in claim 1, wherein said means for producing an output further comprises means responsive to a difference between said constant potential and said predefined voltage, for adjusting said constant potential toward said predefined voltage.

Claim 6

Apparatus as recited in claim 1 wherein the means for comparing comprises a first and a second comparator each having a first and a second input producing a first output when the potential of the first input is greater than the potential of the second input, and a second output when the potential of the first input is less than the potential of the second input, with the said constant potential supplied to the first input of said first comparator and the second input of said second comparator, and said predefined voltage applied to the second input of said first comparator and the first input of said second comparator.

Claim 7

Apparatus as defined in claims 1, 2 or 5 further comprising low pass filter means for removing high frequencies from said output.

Claim 8

Apparatus for fixing the position of a positionable magnetic head responsive to a first and a second potential, and monitoring the position thereof by comparison with a first and a second predefined voltage, said apparatus comprising: a positionable magnetic head; means for applying a first and a second constant potential to the positionable magnetic head so that the positionable magnetic head is rigidly held in a fixed position; means for determining the difference between the first and the second potential; means for comparing said difference with the first and the second predefined voltage; means for signaling if said difference is greater than said first predefined voltage; and, means for signaling if said difference is less than said second predefined voltage.

Claim 9

Apparatus for fixing the position of a positionable magnetic head responsive to a first and a second potential, and monitoring the position thereof by comparison with a first and a second predefined voltage, said apparatus comprising: a positionable magnetic head; means for applying a first and a second constant potential to the positionable magnetic head so that the positionable magnetic head is rigidly held in a fixed position; means for determining the difference between the first and the second potential; means for comparing said difference with the first and the second predefined voltage; means for signaling if said difference is greater than said first predefined voltage; and, means for signaling if said difference is less than said second predefined voltage.

Claim 10

Apparatus as recited in claim 7 wherein said positionable magnetic head comprises a magnetic head mounted on a piezoelectric bender element formed of two piezoelectric ceramic plates bonded to an intervening substrate and sandwiched between two electrodes, for effecting position of said magnetic head in response to said first and second potential.

Claim 11

Apparatus as recited in claim 7 wherein said positionable magnetic head comprises: a magnetic head mounted on a thin leaf element that is pivotably mounted on a support element; and, electromagnetic means positioned adjacent to said leaf element for producing magnetic fields for pivotal movement of said leaf in response to said first and second potential.

Claim 12

Apparatus as recited in claim 7 wherein the means for comparing said differences comprises a first comparator having a first and a second input producing a first output when the potential of the first input is greater than the potential of the second input, and a second output when the potential of the first input is less than the potential of the second input, with the difference between the first and the second predefined voltage being supplied to the first input and the first predefined voltage being supplied to the second input; a second comparator having a first and a second input producing a first output when the potential of the first input is greater than the potential of the second input, and a second output when the potential of the first input is less than the potential of the second input, with the difference between the first and the second predefined voltage being supplied to the second input and the second predefined voltage being supplied to the first input.

Claim 13

Apparatus for controlling the position of a positionable magnetic head, and monitoring the position thereof by comparison with a first and a second predefined voltage, said apparatus comprising: a positionable magnetic head; means for applying a first and a second constant potential to said positionable magnetic head so that the positionable magnetic head is rigidly held in a fixed position; means for determining the difference between the first and the second potential; and means for correcting said constant potential responsive to said difference so that said constant potential is less than said first predefined voltage and greater than said second predefined voltage.

Claim 14

Apparatus for controlling the position of a positionable magnetic head, and monitoring the position thereof by comparison with a first and a second predefined voltage, said apparatus comprising: a positionable magnetic head; means for applying a first and a second constant potential to said positionable magnetic head so that the positionable magnetic head is rigidly held in a fixed position; means for determining the difference between the first and the second potential; and means for correcting said constant potential responsive to said difference so that said constant potential is less than said first predefined voltage and greater than said second predefined voltage.

Claim 15

Apparatus as recited in claim 7 or 11 wherein the means for determining the difference comprises a differential input amplifier having a first and a second input and producing an output equal to the difference between the first and the second input, with the first constant potential being supplied to the first input and the second constant potential being supplied to the second input.

Claim 16

Apparatus as described in claims 1, 7, or 11 further comprising means for effecting alternating monotically decreasing positional displacement of said positionable magnetic head about a predefined quiescent position.

Claim 19

A method as recited in claim 14 wherein said signaling comprises adjusting said constant potential so that said potential is equal to said predefined voltage.

Claim 22

A method as recited in claim 16 wherein said signaling comprises adjusting said first and second potential such that said difference is less than said first predefined voltage and said difference is greater than said second predefined voltage.