Irwin Magnetic Systems, Inc.

Irwin International, Inc.

Joseph H Mueller

Samuel N Irwin

Francis Lum

Marlin K Klumpp

Ronald G Dawson

A recording member for digital data, particularly a recording tape, has a plurality of generally parallel, closely-spaced recording tracks which each contain pre-recorded track-identifying and transducer-positioning servo information, as well as defined data-recording areas. The pre-recorded track-identifying information preferably comprises a digitally-encoded individual track address, and the servo information comprises separate bursts used in centering the transducer upon a particular track. Preferably, each such track has a dedicated area at its beginning, end, or both, which contain continuous repetitions of such positioning information, there being no data areas in such dedicated portions. Digital encoding of track addresses utilizes binary-type code format, accomplished by defining a binary 'zero' as a recorded burst present at a first number of sampling points, and defining a binary 'one' as a burst present at a second number of sampling points of a second duration. The pre-recorded positioning information includes certain non-recorded 'gaps' which serve as initializing signals, and the preferred system for utilizing the pre-recorded, servo-controlled record member utilizes peak-detection and minimum-threshold techniques to accurately distinguish unrecorded gaps from noise, or the like, on the one hand, and to distinguish coded signal bursts from other possible recorded signals, or noise, on the other hand. The preferred system is entirely self-clocking, i.e., the record member does not carry a recorded clock track, and thus does not require the additional transducer required where recorded clock tracks are used; at the same time, the area on the record member otherwise occupied by the clock track is available for data-recording usage.

Data record with pre-recorded transducer positioning signals, and system

A positioner apparatus for moving a transducer head from one to another of a number of parallel tracks extending lengthwise along a recording tape, including a rotary cam with surfaces defining an inclined plane, a cam follower for riding upon such surfaces, a transducer carrier or mount coupled to the cam follower, and guides along which the head carrier is moved by the cam and follower and which serves to index the transducer head at a number of mutually spaced but generally parallel positions extending transversely across the width of the recording tape. Preferably, the rotary cam comprises a wheel-like member having an annular recess around its outermost periphery, with the edges of such recess defining a pair of complementary, spaced, curved ramp surfaces whose path of curvature is concentric with that of the wheel-like member itself. The cam follower preferably comprises a series of laterally spaced rollers which fit into the said cam recess and ride upon the ramp surfaces, such rollers being mounted upon pins or shafts coupled to a slide or block which in turn is coupled to the transducer mount, certain such roller pins being mounted in fixed position to establish a reference, and others being laterally movable to accurately follow the cam surfaces.

Growing community of inventors

Tecumseh, MI, United States of America

Joseph H Mueller