| 摘要 |
PURPOSE:To remove variation of loop gains of a servo system by changing gains of an arithmetic amplifier, which is inserted into an input of a power amplifier driving a voice coil motor in accordance with a control input, in accordance with a force constant of the voice coil motor. CONSTITUTION:A control input 1 is supplied to a power amplifier 5 through an arithmetic amplifier 4, and gains of the arithmetic amplifier 4 are controlled when a resistance connected in parallel to a resistance 2 inserted into an input of said amplifier 4 is set to on or off in acoordance with an output of a read only memory 14. The power amplifier 5 generates an output current proportional to an input voltage, and drives a voice coil motor 6. The read only memory 14 issues an output in accordance with a logical value held by a binary counter 13. According to a analogue switch 3 controlled to be on or off in accordance with the output, a resistance value changes; therefore, gains of the arithmetic amplifier 4 are controlled, and dispersion of a force contstant of the voice coil motor 6 is corrected. |
