| 摘要 |
PURPOSE:To control the rotation of a record disc with a number of revolutions in response to a reproducing position of a pickup, by driving a stepping motor with a drive signal having a phase in response to the count number and obtaining pickup position information for detecting the reproducing position of the pickup. CONSTITUTION:Signals a, b extracted from a counter circuit 15 are amplified at a drive circuit 17 and applied to a motor 14 when the pickup 1 is displaced in the forward direction, to turn forward the pickup to be displaced in the direction of inner circumference. A position signal in response to the reproducing position from the pickup 1 is fed back to a system control circuit 16 to apply servo so as to displace the pickup 1 in a constant speed. On the other hand, a control signal in response to the count number is extracted from the counter circuit 15, and is supplied to a rotating speed setting circuit 18, a speed control signal Vi having an amplitude in response to the control signal is extracted and applied to a rotating speed control circuit 13, where the signal is compared with a rotating speed signal Vo from the record disc 2, a comparison error signal is extracted, and the record disc 2 is controlled so as to be rotated at the number of revolutions in response to the reproducing position of the pickup 1. |
