Conference circuit and bidirectional signal interface - uses input and output stages coupled via signal bus and mixer stage.

摘要

The conference circuit handling audio signals provided by a number of subscribers uses a bidirectional signal interface allowing input signals (ES.i) to be fed from an input stage (2) to a mixer stage (4) supplying an output stage (5), via a bus (3). This has at least the same number of bus lines (3.i) as the number of subscribers (1.i), each coupled to the latter via respective switches (2.i) provided by the input stage (2) at one end and to a respective mixer (4.i) of the mixer stage (4) at the other end. Each mixer output is fed to a controlled amplifier stage (7.i) via a respective output switch (5.i) of the output stage (5). Pref. the output level of each amplifier stage (7.i) is adjusted via the resistance ratio of the input resistance and the feedback resistance for the respective mixer (4.i). ADVANTAGE - Allows individual switching of different inputs and outputs.