Data transducer positioning servo utilizing compensation network and phase-displaced servo signal pairs of like frequency

Claim 3

A system in accordance with claim 1, further comprising means coupled to said terminal for biasing said terminal in accordance with the difference between the actual location of the selected one of the plurality of data transducers and a desired location thereof.

Claim 6

A system in accordance with claim 3, wherein the means for attenuating the error signals, and the means for combining the error signals together comprise a plurality of resistors coupled in series, each of the resistors representing the physical distance between an adjacent pair of transducers on the mechanical element with the junction between each adjacent pair of resistors corresponding to the physical location of a particular transducer along the length of the mechanical element, means coupling each of the opposite ends of the series combination of resistors to receive a different one of the error signals, and means coupling the junction corresponding to the particular one of the data transducers to the means for laterally positioning the mechanical element.

Claim 7

A system in accordance with claim 4, further comprising a printed circuit for imposing a selected bias voltage at each of the junctions between adjacent pairs of resistors to compensate for mislocations of the corresponding transducers along the length of the mechanical element, said printed circuit comprising opposite common buses coupled to respective ones of a pair of voltage sources and conductor means selectively coupling the junctions to the common buses, and further including a resistor coupled between each of selected ones of the junctions and one of the common buses.

Claim 8

A system in accordance with claim 4, further comprising means coupled to at least one of the junctions between adjacent pairs of resistors for imposing thereon a bias voltage, the magnitude and sense of which respectively represent the amount and direction of mislocation of the corresponding transducer from a desired position along the length of the mechanical element.

Claim 9

A system in accordance with claim 6, wherein the means for imposing a bias voltage comprises a pair of voltage sources, a resistor coupled between one of the voltage sources and the junction, and A variable resistor coupled between the other one of the voltage sources and the junction.

Claim 10

A system in accordance with claim 3, wherein said at least two servo tracks have servo signals of like frequency and different phase recorded therealong, the signals in the two different servo tracks presenting successive pairs of alternately positive-going and negative-going signal excursions to the associated servo transducers in response to movement of the record member relative to the common mechanical element.

Claim 11

A system in accordance with claim 8, wherein the servo signals reverse in phase at intervals along the lengths of the servo tracks.

Claim 12

A system in accordance with claim 9, wherein the servo signals are displaced in phase by 90 electrical degrees relative to one another.

Claim 13

A servosystem for aligning a selected one of a plurality of data transducers spaced along the length of a common mechanical element with a selected one of a plurality of data tracks disposed on a record member which is movable relative to the mechanical element, comprising the combination of a pair of servo transducers mounted at the opposite ends of the mechanical element, a pair of servo track sets disposed along the record member, each of the servo track sets being associated with a different one of the servo transducers and having a plurality of spaced apart servo tracks, each adjacent pair of the servo tracks having recorded thereupon signals of like frequency but different phase, means for initially adjusting the lateral position of the mechanical element relative to the record member to position each of the servo transducers adjacent to and between a selected adjacent pair of the servo tracks in the associated servo track set, means coupled to each of the servo transducers for generating an error signal representative of the direction and degree of displacement of the transducer from an imaginary center line between the selected adjacent pair of the servo tracks, an actuator for laterally positioning the mechanical element relative to the record member in response to an applied signal, a serial combination of resistors coupled to receive the error signals at the opposite ends thereof, a selecting switch having a plurality of terminals coupled to different ones of the junctions between adjacent pairs of resistors in the serial combination and a wiper arm coupled to the actuator, and means providing a bias voltage of selected magnitude and sense at each of the junctions between adjacent pairs of resistors.

Claim 14

A servosystem for aligning a selected one of a plurality of data transducers spaced along the length of a common mechanical element with a selected one of a plurality of data tracks disposed on a record member which is movable relative to the mechanical element, comprising the combination of a pair of servo transducers mounted at the opposite ends of the mechanical element, a pair of servo track sets disposed along the record member, each of the servo track sets being associated with a different one of the servo transducers and having a plurality of spaced apart servo tracks, each adjacent pair of the servo tracks having recorded thereupon signals of like frequency but different phase, means for initially adjusting the lateral position of the mechanical element relative to the record member to position each of the servo transducers adjacent to and between a selected adjacent pair of the servo tracks in the associated servo track set, means coupled to each of the servo transducers for generating an error signal representative of the direction and degree of displacement of the transducer from an imaginary center line between the selected adjacent pair of the servo tracks, an actuator for laterally positioning the mechanical element relative to the record member in response to an applied signal, a serial combination of resistors coupled to receive the error signals at the opposite ends thereof, a selecting switch having a plurality of terminals coupled to different ones of the junctions between adjacent pairs of resistors in the serial combination and a wiper arm coupled to the actuator, and means providing a bias voltage of selected magnitude and sense at each of the junctions between adjacent pairs of resistors.

Claim 15

A data transducer positioning servosystem comprising a common mechanical element, a record member movable relative to the common mechanical element and having at least one data track thereon and servo signals of like frequency recorded thereon along at least two spaced apart servo tracks, at least one data transducer mounted on the common mechanical element, at least one servo transducer mounted on the common mechanical element for simultaneously sensing the servo signals in the at least two spaced apart servo tracks, said servo signals being displaced in phase relative to one another so as to present successive pairs of alternately positive-going and negative-going signal excursions to the servo transducer in response to movement of the record member relative to the common mechanical element, and means coupled to the servo transducer and responsive to the signal excursions in the two spaced apart servo tracks for generating an error signal representative of the location of the servo transducer relative to the servo tracks.

Claim 16

A data transducer positioning servosystem comprising a common mechanical element, a record member movable relative to the common mechanical element and having at least one data track thereon and servo signals of like frequency recorded thereon along at least two spaced apart servo tracks, at least one data transducer mounted on the common mechanical element, at least one servo transducer mounted on the common mechanical element for simultaneously sensing the servo signals in the at least two spaced apart servo tracks, said servo signals being displaced in phase relative to one another so as to present successive pairs of alternately positive-going and negative-going signal excursions to the servo transducer in response to movement of the record member relative to the common mechanical element, and means coupled to the servo transducer and responsive to the signal excursions in the two spaced apart servo tracks for generating an error signal representative of the location of the servo transducer relative to the servo tracks.

Claim 17

A data transducer positioning servosystem in accordance with claim 12, wherein said servo signals are displaced in phase by 90 electrical degrees relative to one another.

Claim 18

A data transducer positioning servosystem in accordance with claim 12, wherein the servo transducer comprises a magnetic head, the record member has a magnetizable surface portion on which the servo tracks are disposed, and the servo signals comprise puLses of substantially rectangular waveform recorded by magnetic saturation of alternate sense along the lengths of the servo tracks.

Claim 19

A data transducer positioning servosystem in accordance with claim 12, wherein said servo signals reverse in phase at intervals along the length of the servo tracks.

Claim 20

A data transducer positioning servosystem in accordance with claim 12, wherein the servo transducer responds to movement of the record member relative to the common mechanical element by generating a combined signal comprising two different sets of components respectively representative of the strength of the positive-going and negative-going signal excursions of each of the two different servo signals at the servo transducer, and wherein the means for generating an error signal comprises means coupled to receive the combined signal for separating the two different sets of components, means responsive to each of the two different sets of components for generating a signal amplitude representative of the amplitudes of the components in each set, and means for combining the signal amplitudes from the two different sets of components to provide the error signal.

Claim 21

A data transducer positioning servosystem in accordance with claim 16, further including synchronizing pulses recorded in spaced apart relation along the lengths of the servo tracks and in phase with one another, each of the synchronizing pulses initiating a reversal in phase of that portion of the servo signal which immediately follows the pulse.

Claim 22

A data transducer positioning servosystem in accordance with claim 17, wherein the means for separating the two different sets of components comprises timing means responsive to each occurrence of synchronizing pulses at the servo transducer for initiating a timing sequence, and gating means responsive to the timing sequence for alternately gating the components of the combined signal into either of two different electrical channels, and wherein the means for generating a signal amplitude comprises separate means within each of the two different electrical channels for integrating the components gated into the associated channel.

Claim 23

A servosystem for aligning a plurality of magnetic data heads carried by an elongated headbar with selected ones of a plurality of parallel data tracks disposed along the recording surface of a generally rectangular magnetic strip record member which is movable relative to the headbar, the data tracks being generally parallel with the direction of movement of the strip record member, comprising the combination of a plurality of generally parallel servo tracks disposed along the recording surface of the strip record member in a direction generally parallel with the direction of movement of the strip record member, servo signals of like frequency magnetically recorded along each of the servo tracks, each of said servo signals differing in phase with the servo signals in the immediately adjacent servo tracks and all servo signals reversing phase at locations spaced along the length of the servo tracks, a magnetic servo head mounted on the headbar, said servo head being initially positioned between a selected adjacent pair of the servo tracks to position the date heads adjacent the selected ones of the data tracks and subsequently sensing the servo signals recorded along the pair of servo tracks to generate a sequence of signal components alternately representative of the two different servo signals in response to motion of the strip record member relative to the headbar, means responsive to the amplitudes of alternate ones of the signal components for generating a first signal having an amplitude representative thereof and a given sense, means responsive to the amplitudes of the remaining ones of the signal components for generating a second signal having an amplitude representative thereof and a given sense, means responsive to the amplitudes of the remaining ones of the signal components for generating a second signal having an amplitude representative thereof and a sense opposite the given sense of the first signal, and means for algebraically summing the first and second signals to provide an error signal, the sense of which represents the direction in which the servo head is located relative to an imaginary center line between the selected adjacent pair of servo tracks and the magnitude of which represents the distance between the servo head and the imaginary center line.

Claim 24

A servosystem for aligning a plurality of magnetic data heads carried by an elongated headbar with selected ones of a plurality of parallel data tracks disposed along the recording surface of a generally rectangular magnetic strip record member which is movable relative to the headbar, the data tracks being generally parallel with the direction of movement of the strip record member, comprising the combination of a plurality of generally parallel servo tracks disposed along the recording surface of the strip record member in a direction generally parallel with the direction of movement of the strip record member, servo signals of like frequency magnetically recorded along each of the servo tracks, each of said servo signals differing in phase with the servo signals in the immediately adjacent servo tracks and all servo signals reversing phase at locations spaced along the length of the servo tracks, a magnetic servo head mounted on the headbar, said servo head being initially positioned between a selected adjacent pair of the servo tracks to position the date heads adjacent the selected ones of the data tracks and subsequently sensing the servo signals recorded along the pair of servo tracks to generate a sequence of signal components alternately representative of the two different servo signals in response to motion of the strip record member relative to the headbar, means responsive to the amplitudes of alternate ones of the signal components for generating a first signal having an amplitude representative thereof and a given sense, means responsive to the amplitudes of the remaining ones of the signal components for generating a second signal having an amplitude representative thereof and a given sense, means responsive to the amplitudes of the remaining ones of the signal components for generating a second signal having an amplitude representative thereof and a sense opposite the given sense of the first signal, and means for algebraically summing the first and second signals to provide an error signal, the sense of which represents the direction in which the servo head is located relative to an imaginary center line between the selected adjacent pair of servo tracks and the magnitude of which represents the distance between the servo head and the imaginary center line.