Speakerphone controlled by a comparator with hysteresis

Details Speakerphone controlled by a comparator with hysteresis Speakerphone controlled by a comparator with hysteresis

1995-05-31

1997-11-25

Zele, Krista M.

Telephonic communications

Substation or terminal circuitry

Conversion of signal form

379388, 379391, H04M 908

Patent

active

056920423

ABSTRACT:
A speakerphone which employs non-linear amplifiers to compress transmit and receive signals, and level detectors to determine levels of the compressed transmit and receive signals. Compressed transmit and receive signal levels are compared against one another by a comparator with hysteresis, to enable one of two speakerphone modes of operation--either a transmit mode or a receive mode. Fixed attenuators are switched into either the receive signal path or into the transmit signal path, depending upon the current speakerphone mode. The speakerphone functions described herein are readily implemented using inexpensive control circuitry and a standard telephone line interface, which can be shared by a telephone handset and other components of an integrated telephone system.

REFERENCES:
patent: 3725585 (1973-04-01), Moniak et al.
patent: 4513177 (1985-04-01), Nishino et al.
patent: 4555596 (1985-11-01), Blomley
patent: 4715062 (1987-12-01), Korsky et al.
patent: 4724540 (1988-02-01), Pace et al.
patent: 4879745 (1989-11-01), Arbel
patent: 5357567 (1994-10-01), Barron et al.
patent: 5398281 (1995-03-01), Kurokawa et al.
patent: 5416416 (1995-05-01), Bisher
patent: 5430796 (1995-07-01), Komoda et al.
patent: 5471528 (1995-11-01), Reesor
patent: 5544242 (1996-08-01), Robinson
Motorola Semiconductor Technical Data for MC34118, entitled Voice Switched Speakerphone Circuit, pp. 2-365 to 2-384, Motorola, Inc., USA, 1989.

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