Method and apparatus for processing positioning signals in a record

A recording device comprising:

• (a) a head for writing and reading information;
• (b) a record medium having head positioning information written thereon and tracks each having:
• (b1) a data area on which data is written in a predetermined direction;
• and
• (b2) a position correction information area on which head position correction information is written at a position offset from said data area;
• (c) first means operable in response to said head positioning information to generate a first positioning signal for bringing said head to a predetermined track;
• (d) second means operable in response to said first positioning signal to generate a second positioning signal for bringing said head to a position correction information area;
• (e) position correction information writing control means operable in response to said second positioning signal to bring said head to said position correction information area for writing said position correction information;
• and `(f) position correction information reading control means operable in response to said first positioning signal to position said head and in response to said position correction information to correct a position of said head;
• wherein said first means comprises a position error detection circuit operable in response to said positioning information to detect a position error between said head and a track center to generate two positioning signals A and B which are continuous and periodic over all tracks and offset a quarter period in phase;
• said second means comprises:
• an addition amplifier circuit for summing said positioning signals A and B to generate a sum signal and amplifying said sum signal by a half to generate a positioning signal C;
• and
• a subtraction amplifier circuit for subtracting said positioning signal B from said positioning signal A to generate a differential signal and amplifying aid differential signal by a half to generate a positioning signal D;
• and
• position correction information reading control means comprises:
• a position control circuit operable in response to window signals obtained from comparative operations on said positioning signals A-D and their inverted signals to select a signal from the group consisting of said positioning signals A-D and their inverted signals for generating a linear signal;
• a position correction circuit operable in response to said linear signal to generate a feedback signal for controlling the position of said head so that said linear signal becomes zero;
• and
• an offset detection circuit operable in response to said head position correction information to detect a position error and feed it to said position control circuit and said position correction circuit.

A head positioning method for a recording device which includes a head, a multitrack recording medium, and head positioning information recorded on said recording medium, comprising the steps of:

• (a) generating a first positioning signal from said head positioning information for directing said head to follow a predetermined track, said first positioning signal generating step comprising the steps of
• reading said head positioning information from said recording medium;
• creating a position signal A which intersects a zero signal line at the center of every other track and increases in absolute value when said head moves off said center;
• and
• creating a position signal B which intersects said zero signal line at the center of every other track at which said position signal A does not intersect said zero signal line and increases in absolute value when said head moves off said center;
• (b) generating a second positioning signal from said first positioning signal for directing said head to follow a predetermined intermediate track between two adjacent tracks, said second positioning signal generating step comprising the steps of
• creating a position signal C which intersects said zero signal line at the center of every other intermediate track and increases in absolute value when said head moves off said center;
• and
• creating a position signal D which intersects said zero signal line at the center of every other intermediate track at which said position signal C does not intersect said zero signal line and increases in absolute value when said head moves off said center;
• (c) selecting a positioning signal from the group consisting of said first and second positioning signals, said selecting step comprising the steps of
• providing a window signal for selecting a signal from the group consisting of said first and second position signals and their inverted position signals;
• and
• outputting said selected signal as a linear signal corresponding to said window signal, said window signal providing step comprising the steps of creating logic signals based on said position signals A, B, C, and D, and making a logical calculation of said logic signals and their inverted signals for creating said window signal;
• and
• (d) controlling said head according to said selected positioning signal so that said head follows a center of said intermediate track.