| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic field generator or the like which permits appropriate control of an electromagnetic field to be generated. SOLUTION: When a sine wave is supplied from a sine wave oscillator 10 through a resonance capacitor selection circuit 13, an alternating electromagnetic field is generated on a loop coil 14. When detecting the strength of the electromagnetic field of the loop coil 14, a magnetic field strength detection coil 15 supplies an electromagnetic field signal to a control circuit 19. The control circuit 19 controls and regulates the resonance capacitor selection circuit 13 to make a maximum current flow in the loop coil 14 on the basis of the electromagnetic field signal. That is, a resonance capacitor of an appropriate capacity is selected to maximize a resonance point (125 kHz for example). The control circuit 19 regulates a variable resistor 11 to obtain an intended electromagnetic signal (strength of an electromagnetic field) in that state. That is, automatic gain control is performed so as to obtain optimal electromagnetic field strength on the loop coil 14. COPYRIGHT: (C)2006,JPO&NCIPI
|
