| 摘要 |
<p>A tangential tone-arm for a gramophone has a normal pivoting arm on a vertical axis. The axis is movable with respect to the axis of the turntable so that the distance between their centres may be adjusted to maintain the tangential relationship. An electronic sensor may be fitted to the tone arm to detect an error signal and control a servo-system to correct it. This may consist of a light source (L), a fixed photo-resistor (F) and a moving template (Sch) designed to produce error signal for corrective regulator.</p> |
