LINEAR TRACKING ARM DEVICE

摘要

PURPOSE:To achieve the stable linear tracking of an MFB arm by using a phase advancing circuit as a compensating means. CONSTITUTION:Both the output voltages of magnetic effect elements 43 and 44 are processed through the operational amplification of a differential amplifier 51, whose output is passed through a compensator 52 composed of a phase advancing circuit having a polygonal frequency which is about 20-40% of an arm resonance frequency and processed by the output voltage of a differentiator 49 which differentiates the output of an arm-base-position potentio meter 60; and the arithmetic output is processed through the power amplification of a base driving circuit 53 to flow a driving current to a motor 23. As a result, the motor 23 generates driving force which corresponds to the value of the detected movement speed of an arm base 16 on the basis of the turning angle of a tone arm 4, and the arm base 16 moves in a tracking direction together with the tone arm 4, thus performing tracking operation.