EP 0280909 B1 19911030 - CIRCUIT ARRANGEMENT FOR THE DETECTION OF OSCILLATIONS
Title (en)
CIRCUIT ARRANGEMENT FOR THE DETECTION OF OSCILLATIONS
Publication
Application
Priority
DE 3704998 A 19870217
Abstract (en)
[origin: US4845757A] A circuit arrangement for suppressing oscillations, such as acoustic feedback in a hearing aid, has a circuit which recognizes the presence of oscillations in a useful signal, an oscillatory frequency search circuit, and an oscillation modifying circuit controlled by the search circuit. The oscillation modifying circuit suppresses oscillations by filtering. Drift effects are avoided by a frequency clamp-on sub-circuit in the search circuit, which retains the frequency of the recognized oscillation at the modifying circuit, even when the oscillatory signal at the input of the search circuit disappears.
IPC 1-7
IPC 8 full level
H04R 3/02 (2006.01); H04R 25/00 (2006.01)
CPC (source: EP US)
H04R 25/453 (2013.01 - EP US); H04R 25/505 (2013.01 - EP US)
Designated contracting state (EPC)
AT CH DE FR GB IT LI NL
DOCDB simple family (publication)
EP 0280909 A1 19880907; EP 0280909 B1 19911030; AT E69132 T1 19911115; DE 3865859 D1 19911205; DK 169012 B1 19940725; DK 77988 A 19880818; DK 77988 D0 19880216; US 4845757 A 19890704
DOCDB simple family (application)
EP 88101634 A 19880204; AT 88101634 T 19880204; DE 3865859 T 19880204; DK 77988 A 19880216; US 15239088 A 19880204