Coin discrimination apparatus with compensation for external ambient conditions
First Claim
1. Coin discrimination apparatus comprising:
- means defining a path for passage of a coin under test;
sensor coil means for forming an inductive coupling with said coin under test during its passage along the path;
drive means for generating an oscillatory electrical signal across the coil sensor means;
detecting means responsive to the amplitude of the oscillatory signal across the sensor coil means in the absence of a coin, for producing an ambient condition signal (t) which is a function of an ambient condition for the sensor coil means;
control means responsive to the amplitude deviation of the signal across the sensor coil means produced as a result of the inductive coupling between a coin traveling along the path past the sensor coil means, for providing a coin signal (x) which is a function of a characteristic of the coin uncompensated for the effects of said ambient condition;
compensating means for modifying the coin signal (x) to produce a compensated coin signal (y) according to the following equation;
space="preserve" listing-type="equation">y=k((c.sub.1 x+c.sub.2)t+x)+c.sub.3 wherek, c1, c2, c3 are constants;
memory means including at least one set of reference data for said compensated coin signal (y); and
means for determining whether the compensated coin signal (y) is in a predetermined relationship with said reference data and providing an output indicative of whether the coin is acceptable.
1 Assignment
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Accused Products
Abstract
A coin validator includes improved compensation circuitry for compensating for ambient conditions such as temperature or the presence of metallic objects, includes a path (1) for passage for coins under test, sensor coils (2, 3, 4) which form an inductive coupling with coins under test during their passage along the path, detectors (DM1, ADC) responsive to the impedance presented by the coil in the absence of a coin, for producing an ambient condition signal which is a function of an ambient condition such as temperature of the presence of metallic objects a controller (MPU 17) responsive to the inductive coupling between a coin travelling along the path past the coil, for providing signal which is a function of a characteristic of the coin, and a microprocessor (MPU) for modifying operation of the controller in dependence upon the ambient condition signal.
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Citations
19 Claims
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1. Coin discrimination apparatus comprising:
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means defining a path for passage of a coin under test; sensor coil means for forming an inductive coupling with said coin under test during its passage along the path; drive means for generating an oscillatory electrical signal across the coil sensor means; detecting means responsive to the amplitude of the oscillatory signal across the sensor coil means in the absence of a coin, for producing an ambient condition signal (t) which is a function of an ambient condition for the sensor coil means; control means responsive to the amplitude deviation of the signal across the sensor coil means produced as a result of the inductive coupling between a coin traveling along the path past the sensor coil means, for providing a coin signal (x) which is a function of a characteristic of the coin uncompensated for the effects of said ambient condition; compensating means for modifying the coin signal (x) to produce a compensated coin signal (y) according to the following equation;
space="preserve" listing-type="equation">y=k((c.sub.1 x+c.sub.2)t+x)+c.sub.3where k, c1, c2, c3 are constants; memory means including at least one set of reference data for said compensated coin signal (y); and means for determining whether the compensated coin signal (y) is in a predetermined relationship with said reference data and providing an output indicative of whether the coin is acceptable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification