| 摘要 |
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.
|
