Full duplex speakerphone for radio and landline telephones

Details Full duplex speakerphone for radio and landline telephones Full duplex speakerphone for radio and landline telephones

1984-12-14

1986-12-16

Lev, Robert G.

Telephonic communications

Having light wave or ultrasonic link for speech or paging...

Including fiber optic link within telephone network

379390, 379411, H04Q 704

Patent

active

046298290

ABSTRACT:
A full duplex speakerphone employing adaptive filters and having application in radiotelephone systems is disclosed. To cancel acoustic feedback echo of the receive signal, a representation of the receive signal is subtracted from the transmit signal generated by the speakerphone microphone. The adaptive filter receive signal representation coefficents are modified when the receive signal is detected. Likewise, to cancel electronic echo of the transmit signal, a representation of the transmit signal is subtracted from the receive signal. The adaptive filter transmit signal representation coefficients are modified when the transmit signal is detected.

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