Acoustic feedback coupling disturbance suppression arrangement - has successive circuit stages operating on desired and undesired components
ES431501A1
Procedure and apparatus to cancel acoustic feedback. (Machine-translation by Google Translate, not legally binding)
ES431500A1
Improvements in microphonic units. (Machine-translation by Google Translate, not legally binding)
JPS5151205A
Onkyokikanochikesu sochi oyobi hoho
IT1024704B
Microphone with sound sensitive element - mounted symmetrically in housing, for disturbing noises to equally effect both sides reduces interference to minimum
AU7449574A
Microphone
GB1294306A
A display device for use with a telephone instrument
