Telephonic communications – Multi-line or key substation system with selective switching...
Patent
1996-07-08
1998-06-30
Kuntz, Curtis A.
Telephonic communications
Multi-line or key substation system with selective switching...
379390, 379391, 379392, H04M 100
Patent
active
057745366
ABSTRACT:
A balanced network in a keyphone system has a filtering unit which is composed of: first and second filtering circuits, formed on the transmission path and having an inverted-phase feature, for adjusting the level of the transmission signal and for removing spurious waves thereof; an inverted-phase signal branch point disposed between the first and second filtering circuits, for branching out an inverted-phase transmission signal; an operational amplifier disposed on the reception path, for adjusting a level of the reception signal; a signal superimposing node disposed ahead of an input of the operational amplifier; and a feedback signal level adjusting circuit disposed between the inverted-phase signal branch point and the signal superimposing node, for adjusting the level of the inverted-phase transmission signal which has been branched out from the inverted-phase signal branch point so as to reduce a feedback signal, transmitted from the transmission path to the reception path through the common node, to a desirable level.
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Barnie Rexford
Bushnell Esq. Robert E.
Kuntz Curtis A.
Samsung Electronics Co,. Ltd.
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