| 摘要 |
PURPOSE: A driver and a servo method of constant-speed movement are provided to stably embody the movement of constant speed in any speed within a certain speed range without regard to an individual characteristic of a recorder/player and a stance. CONSTITUTION: At patching a upper position and a lower position, a speed value at each sampling time, a sample value of scale signal at that time, a difference of the sample value of the scale signal before a first sampling time are yielded during sampling the scale signal at a 80microseconds interval. A control voltage is generated to equal the speed value required at each sampling time as the measuring speed value to a reference speed value set according to a target speed. A magnetic driving circuit(119) feeds a current to a voice coil motor coil of a moving tool(16) according to the control voltage. The scale signal is a waveform that a first data track is approximated to a sine wave. To use the scale signal in a servo of constant speed, the reference speed value is set by regarding a part of half track as a vertical part in the scale signal of sine waveform.
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