Conference system for telephony

摘要

A conference system comprises a conference circuit to which a plurality of participants are connected via terminals respective connecting circuits having input and output circuits, the signal from the output circuits being fed to the connecting circuit and signals from the conference circuit being fed lines to the input circuits. The conference circuit has summing amplifiers (10 to 13) whose inputs are connected to the outputs of the connecting circuits so that the output signals from the connecting circuits are algebraically summed. The signs of the signals to be summed are determined from the relationship E-S* S=O where E is the unity matrix and S* is the transposed complex conjugate matrix of S.