| 摘要 |
<p>A method and apparatus for coin examination which transmits on one side of a coin a low frequency electromagnetic field from a transmitter inductor which is part of a transmitter circuit, monitors the frequency of the low frequency electromagnetic field, receives a portion of the field on the other side of the coin with a receiving inductor which is part of a receiving circuit, measures the phase shift between the transmitted signal and the received signal, and determines if the measured phase shift corresponds to the phase shift for an acceptable coin at the monitored frequency.</p> |
