Method and apparatus for controlling transducer

Apparatus for controlling the position of a transducer mounted for movement across data tracks on a recording medium, said apparatus comprising:

• a transducer mounting assembly including an elongated arm supporting a transducer near one end thereof and being mounted for rotation about an axis near the opposite end of said arm, said assembly being positioned so that said transducer is movable across the data tracks, in operative overlying relation thereto, in response to rotation of said arm;
• drive means operable for rotatably driving said arm about said axis;
• and
• control means for controlling the position of said transducer with respect to selected data tracks, said control means including;
• (a) a pair of magnetic sensing probes mounted on said arm, near said other end, for rotation with said arm over a sensing path, said probes being spaced with respect to each other in leading and lagging relation in the direction of arm rotation;
• (b) magnetic means for defining a magnetic field having a field strength that varies linearly over said sensing path in the path of travel of said probes so that said probes provide signals indicative of the relative positions of said probes along said sensing path;
• (c) means for providing a track address signal indicative of a selected data track;
• (d) signal processing means for receiving said track address signal and said probe signals and deriving therefrom a control signal for operating said drive means to effect arm rotation so said transducer is positioned over the selected track.