Self tuning low frequency phase shift coin examination method and apparatus
US4493411A · kind A · utility
10Cited by
2References
25Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 29, 1982 |
| Grant date | Jan 15, 1985 |
| Priority date | — |
| Expiry date | Sep 29, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D5/08
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.