| 摘要 |
PURPOSE: To suppress vibration through a digital notch filter by performing a notch filter operation for an output signal from a controller at a rate predetermined times as high as the sample frequency and outputting the result as an actuator control signal. CONSTITUTION: A magnetic disc takes in positional error signals 14 at a sample frequency (f) into a DSP1 through a magnetic head 7. Similarly, drive current signals 12 for an actuator 6 are taken in at same sample frequency (f) and a controller 2 having designed sample frequency of (f) generates a controller signal 10. A notch filter 3 suppressing mechanical resonance has a designed sample frequency of 2f and receives the control signal 10 being updated every other time. A control signal 11 for the actuator is outputted at a sample frequency of 2f from the DSP1. Since a resonance point of double frequency can be dealt with, effect of mechanical resonance having frequency equal to the Nyquist frequency of controller or above can be suppressed. |
