| 摘要 |
A telephone conference system includes a number of units (1), each of which provides a speaker or speakers (7) connected via an amplifier (6) to a receiving line, a preamplifier-mixer (3) unifying the outputs of a plurality of microphones (2a ... 2n, 8a, 8b), and a summing amplifier (5) unifying the output of the preamplifier-mixer (3) and the output of a microphone or microphones from another unit, the output of the summing amplifier (5) being connected to another unit in series or to telephone apparatus (not shown). |
