| 摘要 |
<p>A head positioning servomechanism positions a read/write head (16) over a rotary, magnetic, informational data storage disc (10). It uses as its positional feed back element a two-phase optical detente (22, 24). It overcomes the positioning errors caused by phase errors between the two position-indicating signals by having the repetition distance of the two signals from the detente (22, 24) equal to the regular spacing between data tracks on the disc (10). One of the tracks is a servo track (14). A selector (25) exclusively provides for positioning the head (16) that position feed back signal of the two available, which brings the head (16) over the servo-track (14) with least error. The positioning is achieved applying correction for the error via a D/A converter (30). The situation is checked from time to time by a controller (34). </p> |
