Record track following and seeking

A record member having a plurality of parallel signal tracks, said tracks being divided into bands of tracks spaced apart a given distance;

• said record member having track location indicator means including in combination:
• two groups of signal bursts recorded on the member for indicating a given number of track location lines and disposed along the length of the identified tracks in closely spaced relation;
• said signal bursts in a first of said bands being aligned transversely to the lengths of said center lines and being spaced apart about one-half said given distance with aligned leading edges;
• said signal bursts in a second of said bands being aligned transversely to the lengths of said center lines and being spaced apart about one-half said given distance and having aligned trailing edges;
• and
• said signal bursts in said bands being in alternate pairs of one signal burst from each group centered on adjacent ones of said location lines and disposed on opposite sides of a given one of said locating lines and abutting said given one center lines, respectively.

A record member having identifying track locating lines for addressing parallel record tracks,

• improved track locating line identification patterns, including in combination:
• a plurality of servo signals aligned transversely to length of said locating lines, for each track locating line there being a plurality of longitudinally spaced servo signals, one of which is substantially symmetrically disposed about said each track locating line and another one of which substantially abuts said each track locating lines;
• and
• said servo signals for predetermined ones of said track locating lines being of differing durations along the track length.

A record member having a pluarlity of servo sector areas for identifying a plurality of record track location lines,

• the improvement including in combination:
• a plurality of spaced-apart servo signal burst groups extending along said track location lines in each said servo sector areas and said groups extending transversely to said track location lines and having servo signal bursts apart transversely to said track location lines, said groups yielding a repetitive geometric pattern along a direction transverse to said track location lines;
• and
• said servo signal bursts respectively having a plurality of signal characteristics distributed respectively in each servo area in accordance with a predetermined pattern whereby said pattern of signal characteristics and said geometric pattern yield a repetitive pattern encompassing a number of track location lines substantially greater than a number of track location lines encompassed by said first-mentioned repetitive pattern while providing enhanced off-track recovery.

A track seek and follow circuit for use with a record member having a plurality of parallel tracks, each track identifiable by a unique sequence of predetermined signal bursts;

• means for reading said signal bursts and supplying servo signals derived therefrom;
• the improvement including in combination:
• burst length comparator means for measuring and supplying an indication of the duration of said servo signals;
• control means responsive to said indication to supply a set of control signals in accordance with said indications;
• integrator means receiving said servo signals and responsive to said control signals to integrate said received servo signals at a rate in accordance with said control signals to thereby weight amplitudes of said servo signals;
• and
• first compare means for comparing said integrated servo signals from successive signal bursts in said sequence and supplying a position error signal in accordance with said comparison.

A servo signal processing circuit including in combination:

• a first controllable integrator means for integrating a sequence of servo signals;
• a second controllable integrator means for integrating only a given one servo signal of said sequence of servo signals;
• a PES generator responsive to said first integrator means to generate a PES signal in accordance with said second integrator means integration;
• and
• means for controlling both said integrator means in accordance with predetermined servo characteristics.

Magnetic storage apparatus having a circular-like record member with a plurality of record tracks having locations defined by a plurality of parallel track location lines spaced apart a given distance, a transducer, means supporting said record medium and transducer for relative movement along and transverse to said track location lines for scanning said record medium to sense servo signals recorded in said servo sectors,

• the improvement including in combination:
• said member having circumferentially interleaved and radially extending data and servo sectors;
• each said one servo sector including a plurality of groups of circumferentially displaced servo positioning signals, each said servo sector exhibiting a repetitive pattern of said servo signals along radii of said record member, respectively, servo signals in one of said groups having circumferential lengths complementary to lengths of servo signals in another of said groups;
• servo signal processing means responsive to said servo signals sensed by said transducer to simultaneously identify a desired track and supply a position error signal indicative of positioning errors and in accordance with said identified track;
• and
• a servomechanism responsive to said position error signal to actuate said supporting means to relatively move said transducer and record member toward said desired track.

The method of indicating positioning relatively movable record and transducer members, said record member having servo signals for each desired position exhibiting a given servo energy to sequence positional relationship,

• the steps of:
• positioning said members to approximately said desired position;
• indicating said given energy sequency relationship;
• measuring a calibrating energy from one of said servo signals;
• measuring servo energy sensed by said transducer;
• calibrating said servo energy measurement in accordance with measured calibrating energy of one of said servo signals in said sector;
• and
• comparing said indication with said mesurement to generate a position error signal.

The method of recovery from an off-track positioning error in a track following servo operating with a record member having sequential laterally offset track position indicia, said indicia having plural unique sensible signal characteristics,

• the steps of:
• sensing for and measuring a first of said unique sensible signal characteristics associated with a track position to be followed;
• sensing for and measuring a second of said unique sensible signal characteristics associated with a track position immediately adjacent to said track position to be followed;
• sensing for and measuring other signal characteristics indicative of track following off-centered position;
• and
• combining said measurements to generate an error signal in a given proportionate relationship to positioning error indicated thereby.

The method of detecting track position error of a transducer relatively positionable with respect to a desired track position of a record member having a plurality of record tracks, each track position indicatable by a combination of laterally offset successively received servo signals each having one of a plurality of predetermined signal characteristics distributed among said servo signals in a predetermined pattern,

• the steps of:
• sensing and memorizing said signal characteristics of successively received servo signals;
• sensing and memorizing amplitudes of said successively received signals;
• combining said memorized characteristics and amplitudes to indicate track position error.