| 摘要 |
<p>Digital conference bridge for use with a plurality of telephones (#1 ...#0) and arranged whereby in accordance with predetermined output conditions from the telephones, as existing from time to time during use of the telephones for communication therebetween, the output signal from one telephone is directed to the remainder of the telephones and the output signals of the remainder are suppressed. The bridge generates products x<Sub>n</Sub>.g<Sub>n</Sub> and x<Sub>i</Sub>-g<Sub>i</Sub> where x<Sub>n</Sub> and x<Sub>i</Sub> are instantaneous magnitudes of samples of all of the signals and of the selected signal respectively, and g<Sub>n</Sub>and g<Sub>i</Sub> are predetermined gain factors for all of the signals and for the selected signal respectively. A register (60) storing the value of "i", designating the presently selected telephone, is updated by a circuit including comparators (42, 52) connected to a gate (44) whereby to surplant a selection of an existing value of "i" by a new value under the following conditions:<MathDetails id="matha01"><MathText><![CDATA[ <img id="ia01" file="imga0001.tif" wi="19" he="5" img-content="math" img-format="tif" inline="no" /> ]]></MathText></MathDetails>and<MathDetails id="matha02"><MathText><![CDATA[ <img id="ia02" file="imga0002.tif" wi="21" he="4" img-content="math" img-format="tif" inline="no" /> ]]></MathText></MathDetails></p><p>One of the comparators (42) is arranged to compare the last held values xi-gi as stored in a register (40) with the incoming products x n-gn, to determine whether the first of these conditions prevails and the second comparator (52) is arranged to compare the incoming product xn-gn with the product T.gn to determine whether the second of these conditions prevails. The value "T" represents a threshold value stored in the threshold register (48). The bridge is arranged to replace a threshold "T" as stored in the threshold register (48) by a new value equal to xi.gi in the event that a product xi-gi should exceed the existing value of "T". The bridge is also arranged to decrement the threshold value "T" by a predetermined amount in the event that the threshold value "T" should exceed one or a plurality of successive products xi-gi.</p> |
