🚀 go-pugleaf

Users of PABX systems may well be familiar with the conferencing
facilities they frequently provide, whereby three (or sometimes more)
parties may take part in a conversation. I am investigating providing
this function in a digital phone, for three party only. Effectively,
in each phone there may be two incoming digital streams, which will
be combined and fed to the earpiece. The question is: how should this
combination be done? I have seen schemes in which the "loudest"
speaker is determined, and others excluded. This seems inappropriate
to me, although it is an option. Summing the inputs seems simple
in practice, however it is not obvious how effective this is. Is
overflow a problem in real life, or does the random nature of the
signals, and the fact that practical conversations have only one
speaker at a time, prevent it from occurring to any significant
degree? What other problems may occur?

I am hoping to find examples of real applications of this, but am
having trouble finding papers/books which refer to this subject. 
Finding appropriate keywords seems to be a problem. Can anyone
point me in the direction of any work which has been published
in this area. Actual implementations in either software or hardware
of multi-party conferencing by any technique are of particular
interest.

Thanks to anyone who can help,

Mark.
------------------------------------------------+-----------------------------+
Mark Summerfield, Telecom Research Laboratories | "A witty saying proves      |
ACSnet[AARN/Internet]: m.summerfield@trl.oz[.au]|       nothing." -- Voltaire |
Snail: PO Box 249, Clayton, Vic., 3168          +-----------------------------+