| 摘要 |
A detector device adapted to be used for detecting coins and other metal objects for various purposes including to distinguish between genuine and non-genuine or counterfeit coins, the subject detector device includes an electric tank circuit having a coil through which, or adjacent to which, an object or coin to be detected moves, apparatus to electrically shock the tank circuit to produce an output representative of the object or coin and represented as a damped wave signal the frequency and shape of which depends on the electrical characteristics associated with the tank circuit and on the physical and electric characteristics of an object or coin being detected, and a detector circuit operatively connected to the tank circuit including circuit elements connected to respond to one or more characteristics of the damped wave output. The detector circuit may optionally include circuit elements connected to respond to the shape of the envelope of the output, the number of cycles of the output that exceed some predetermined value, the time required for a number of cycles that exceed some preselected value to take place and/or to pronounced changes that occur in the shape of the envelope such as to a marked change in the rate of decline of the damped wave output. The present detector device optionally may also include other circuitry operatively connected thereto to modify the shape of the envelope, to establish time spaced electrical shocks of the tank circuit, to count cycles of the damped wave output that exceed some preselected value, and the device may include a cycle counter apparatus, a decoder circuit, and/or an apparatus actuatable in response to the occurrence of one or more predetermined parameters of the damped wave that are used to distinguish between objects that differ from one another in some one or more respects.
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