| 摘要 |
A system detects a change in object presence in a magnetic field generated from a coil (205). A low amplitude signal near the resonant frequency is injected into the coil (205) until the system comes to equilibrium. At this point the feedback is measured. The feedback signal can be measured as at least one of several signals, for example, but not limited to the voltage on the resonant capacitor (203), the current in the coil (205), or the voltage between the resonant capacitor (203) and the coil (205). A change in the steady state response indicates a change in device presence. |
