METHOD AND DEVICE FOR SELECTING COIN

摘要

A coin to be judged is passed near an oscillation coil excited by an exciting signal containing a plurality of harmonic components, that is nonsinusoidal alternating current, and the coin is sorted in accordance with a signal produced by a receiving coil electromagnetically coupled with the oscillation coil and containing at least two harmonic components. The signal induced in the receiving coil may be a composite signal of at least two harmonic components. This signal may consist of a first signal of a composite of at least two harmonic components and a second signal of a composite of at least two other harmonic components.