| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that a levitation control current in an electromagnet dominantly includes components having frequencies lower than sensing carrier frequencies and so, when sensing carrier components are only extracted from an electromagnet current and amplified, it is difficult to increase the SN ratio of a position detecting signal. <P>SOLUTION: When the sensing carrier components mixed in a driving signal from the electromagnet MG are detected to detect a distance x between a supported body 12 and the electromagnet MG, the sensing carrier components flowing in a bypass capacitor C connected between the power supply terminals of an electromagnet driving circuit 6 are detected. As a result, the SN ratio of the position detecting signal can be increased. This focuses on the fact that the sensing carrier components having high frequencies are dominantly supplied from the bypass capacitor C. <P>COPYRIGHT: (C)2013,JPO&INPIT |
