The definitive paper on noise, bandwidth and their relationships in a
communications channel is still Claude Shannon's 1948 paper "A
Mathematical Theory of Communication":
http://cm.bell-labs.com/cm/ms/what/shannonday/paper.html
It's the signal to noise ratio in the channel that will determine if
a given voice bandwidth will get through, and how much of the power
in that bandwidth will actually be useful to communicate information.
It's also why DXers tend to favor narrower TX bandwidths, since they
tend to operate in marginal S/N conditions.
Most modern USAF fixed station radios use 2.8 kHz as a default
bandwidth (at least all the Motorola MiComm II we use).
The PolyComm article is based on a noiseless channel, BTW, so it is
not surprising that it concludes that the wider bandwidths are best
for intelligibility. Unfortunately, this is not the case on HF comm
channels much of the time due to fading, interference, and noise.
73,
Chuck KE3KR
<begin quoted mail>
Interesting, although I have to take into account the fact that the
publisher of the report has a vested interest in showing that more
bandwidth is appreciably better for voice communication.
73, doug
Date: Fri, 29 Jun 2007 15:09:34 -0400
From: "DOUGLAS ZWIEBEL" <[EMAIL PROTECTED]>
http://www.polycom.com/common/documents/whitepapers/
effect_of_bandwidth_on_speech_intelligibility_2.pdf
Don't confuse single single intelligibility of speech (and
especially
speech quality) with speech intelligibility during heavy band qrm.
It's always a balancing act.
Argh. This is why I have forgotten "the phone" and concentrate
on cw.
de Doug KR2Q
<end quoted mail>
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
