公开(公告)号：US3882276A

公开(公告)日：1975-05-06

申请号：US45370574

申请日：1974-03-22

Applicant: BELL TELEPHONE LABOR INC

Inventor： FEINER ALEXANDER ,  JAMES DENNIS BRYAN

IPC: H04B3/03 ,  H04M3/42 ,  H04M3/56 ,  H04M9/08

CPC classification number: H04M3/561

Abstract: In lossless or low loss conferencing systems it is customary to use a hybrid to convert each station from 2-wire to 4-wire operation. Because of impedance mismatch conditions, reflections can occur at the hybrid interface thereby causing echo and ''''singing'''' problems. Self-cancellation of the reflected signals can be achieved by reversing the phase of the reflected signals through the hybrids and assigning the reversed phase hybrids only to stations connected to the system by trunks. For those stations connected to the system by lines, 5dB pads are used in conjunction with unreversed phase hybrids. In this way complex switching is avoided.

Abstract translation: 在无损或低损耗会议系统中，通常使用混合动力将每个站从2线转换为4线操作。 由于阻抗失配条件，混合界面可能发生反射，从而引起回声和“唱歌”问题。 反射信号的自消除可以通过将反射信号的相位反转通过混合动力并将逆相混合器仅分配给通过干线连接到系统的站来实现。 对于通过线路连接到系统的那些站，5dB焊盘与未反相相位混合使用。 以这种方式避免了复杂的切换。