Electrical audio signal processing systems and devices – Hearing aids – electrical – Specified casing or housing
Patent
1994-07-18
1997-10-14
MacDonald, Allen R.
Electrical audio signal processing systems and devices
Hearing aids, electrical
Specified casing or housing
395 234, 381 93, 381 83, G10L 302, G10L 900, H04R 2700, H04B 1500
Patent
active
056779879
ABSTRACT:
An A/D converter converts an analog signal to a digital signal. A plurality of cascade-connected notch filters include a first notch filter which is connected to the output of the A/D converter. A D/A converter is connected to the output of the last stage notch filter for converting a digital signal to an analog signal. The output of the last stage notch filter is connected to the input of a fast Fourier transform unit for analyzing the frequency. Analysis results of the fast Fourier transform unit are supplied to a detector. A coefficient having the same center frequency as that of a peak frequency outputted from the detector is selected from a coefficient memory and it is transferred to a second coefficient memory. Thus, the frequencies of the notch filters are set to eliminate howling.
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Kawamura Akihisa
Onizuka Kazuhiro
Seki Nobuyuki
Edouard Patrick N.
MacDonald Allen R.
Matsushita Electric - Industrial Co., Ltd.
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