Multiple tone signaling device
US4558305A · kind A · utility
22Cited by
8References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1982 |
| Grant date | Dec 10, 1985 |
| Priority date | — |
| Expiry date | Dec 20, 2002 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB06B2201/55
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A multiple tone signaling device provides a piezoelectric transducer, first, second and third oscillator circuits, a first input terminal for enabling either or both of the first and second oscillator circuits, circuitry coupling the third oscillator circuit to the first and second oscillator circuits for disabling either the first or second oscillator circuits in response thereto, and a second input terminal coupled to the third oscillator circuit for allowing control of the output of said third oscillator circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.