Digitally controlled ringer signal generation
US5323456A · kind A · utility
58Cited by
8References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 5, 1992 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Jun 5, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/04
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method and apparatus, of producing an alarm or ringing signal by providing a first pulse signal having a predetermined pulse width to define an alarm or ringing signal amplitude, and modulating the pulse signal with a second pulse signal having a pulse rate at least an order lower than the frequency of the first pulse signal to define the alarm or ringing signal frequency, averaging the modulated first pulse signal in a loudspeaker voice coil and reproducing the result in the loudspeaker to provide the alarm or ringing signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.