PURPOSE:To eliminate a need for providing a head, etc., independently in order to detect the rotational speed of a capstan and to reduce the number of parts by controlling the rotational speed of the capstan by using an AFT (automatic track finding) signal included in a reproduced signal obtained from a head. CONSTITUTION:A reproduced signal RF led by a switch circuit 34 is supplied to a low-pass filter circuit 58, and a pilot signal component P is extracted from the ATF data. This signal P is supplied to an A/D (analog/digital) conversion circuit 59 and converted to a digital data corresponding to its level, and supplied to a latching circuit 60. The latching circuit latches this digital data outputted from the A/D conversion circuit 59 at times when timing signals SP1 and SP2 are respectively supplied, and is outputted to an arithmetic decision circuit (ALU) 62. The ALU 62 executes a subtraction processing between the data supplied to its two input terminals. The rotational speed of the capstan is so controlled that the result of said arithmetic operation is maintained within a prescribed range.
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