| 摘要 |
PURPOSE:To prevent variation in regenerative frequency due to the eccentricity of the center hole of a record by making constant the circumferential speed of the center hole of a record by making constant the circumferential speed of the record at the trace position of a tone arm by controlling the rotating speed of a turntable on the basis of the horizontal moving speed of the tone arm. CONSTITUTION:Turntable 23 is direct driven by DD motor 24, and its rotating speed is detected by frequency generator 26, whose detection signal (a) is supplied to speed servo circuit 27, where speed control signal S for DD motor 24 is generated. Part of speed detection signal (b), obtained from speed detection coil 6 fitted to the tone arm unit, is supplied to speed servo circuit 27. Then, circuit 27 generates a control signal which conpensates the variation in circumferential speed caused by the eccentricity of the center hole of the record and it is supplied to DD motor 24 being superposed upon the above-mentioned speed control signal S. Therefore the rotating speed of motor 24 is controlled according to speed detection signal (b), so that the circumferential speed of the record 25 at the trace point of the stylus caused by the eccentricity of the center hole of record 25 will be constant. |
