Sound surge detector for alerting headphone users
US4827458A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 15, 1988 |
| Grant date | May 2, 1989 |
| Priority date | — |
| Expiry date | Mar 15, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A sound reproducing system including a portable appliance reproducing sound from a recording and a transmission path transmitting reproduced sound to headphones worn by a user, and an apparatus for indicating to the user the occurrence of an abnormal event, causing a surge of ambient sound. The apparatus and a related method pick up ambient sound, transduce the ambient sound to an electrical signal, amplify the electrical signal, provide as a first output signal an envelope of the amplified signal, differentiate the first output signal, produce a second output signal with an amplitude which is a function of the slope of the first output signal, comparing the amplitude of the second output signal to a preset threshold level, and produce a control signal when the second output signal exceeds the threshold level indicating the occurrence of a surge in ambient sound having an amplitude, duration, and rising leading edge exceeding certain minimum characteristics, and indicating to the user the occurrence of an abnormal event through the transmission path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.