Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!pprg.unm.edu!hc!lll-winken!uunet!tektronix!midas!jeffw
From: jeffw@midas.STS.TEK.COM (Jeff Winslow)
Newsgroups: sci.electronics
Subject: Re: Dial tone generation
Message-ID: <3943@midas.STS.TEK.COM>
Date: 1 Feb 89 19:54:22 GMT
References: <349@serene.UUCP> <14094@cup.portal.com>
Reply-To: jeffw@midas.UUCP (Jeff Winslow)
Distribution: usa
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 12

In article <14094@cup.portal.com> ISW@cup.portal.com (Isaac S Wingfield) writes:

>BTW, on the precision dial tone: the frequencies are 350 and 440 Hz,
>with amplitudes chosen so that the lower produces 100% double
>sideband modulation of the upper. The signals are actually just
>summed, but if you look with a 'scope, that's what you'll see.

Hmm. 350Hz 100% DSB modulation of 440Hz gets components at 90Hz and 790Hz;
summing gets components at 350Hz and 440Hz. Could you explain that one
some more?

						Jeff Winslow