The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Phil Allison"
References: <3DEE2757.EE79B063@crf.canon.fr> <3DEFD744.3A2D8C8D@gv.net>
Subject: Re: audio line specifications
X-Newsreader: Microsoft Outlook Express 5.50.4522.1200
Date: Sat, 7 Dec 2002 08:15:03 +1100
NNTP-Posting-Date: Sat, 07 Dec 2002 08:04:08 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
"Watson 'Atto Parsec' Name" wrote in message
> In article ,
> email@example.com mentioned...
> > "Michael R. Kesti" wrote in message
> > news:3DEFD744.3A2D8C8D@gv.net...
> > > Vlad wrote:
> > >
> > > >Yes. The impedance of the line is NOT important.
> > >
> > > The impedance of the line is not usually important, because audio
> > > are usually shorter than the shortest wavelength in the audio band.
> > ** Not again!! This is non relevant. If you need a ( twisted
> > balanced audio line to have a flat response over distances of 100 metres
> > more then correct termination of the line is important. If wavelength
> > the issue then it would not matter until 10 or 15 km.
> I have read many of the followups, and I don't think anyone has
> mentioned the subject of the cable capacitance and why it is necessary
> to have a low enough impedance to prevent the cable capacitance from
> rolling off the high end of the signal. In other words, the line driver
> has to have a low enough impedance to drive the line adequately at the
> highest frequencies, no matter what the length of the line is.
** Correct line termination renders the load resistive.
> be only 3 meters long, but if the driver is a crystal microphone, which
> has a high impedance, then the high end may be rolled off by the few
> hundred pFs of cable capacitance.
** Nonsense. Crystal mics are already capacitors so additional
parallel capacitance drops the level only - not the HF response.
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup