DERP -- you are right. T1 does 24 voice channels, not 16. Thanks for the heads up! Dave
> -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Robert LaJeunesse > Sent: Sunday, January 05, 2014 11:33 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] WWV/WWVH audio simulator? > > The US POTS is digitized at 8KHz sample rate, so Nyquist says > the highest frequency you can accurately digitize is 4KHz. > Allow some for a (fancy digital) filter and 3400Hz is about > the best you can expect. As for T1, almost right. The 8K > samples per second are u-law processed to 8 bits each for > transmission down the line, at 1.544 Mb/s a T1 line handles > 24 streams, plus 8K bits per second of supervisory data. Yes, > a nice round 193 bits per frame. > > Bob LaJeunesse > > > > >________________________________ > > From: DaveH <[email protected]> > >To: 'Discussion of precise time and frequency measurement' > <[email protected]> > >Sent: Sunday, January 5, 2014 1:53 PM > >Subject: Re: [time-nuts] WWV/WWVH audio simulator? > > > > > >This is by design > > > >The POTS (Plain Old Telephone System) specifies a bandwidth > of 300Hz to > >3,400Hz. > > > >http://en.wikipedia.org/wiki/Plain_old_telephone_service > > > >They are trying to cram as many channels into as little bandwidth as > >possible and the greater the frequency response they > provide, the more > >bandwidth it takkes and the fewer channels they can provide. > > > >T1 lines were originally developed to bring 16 voice channels into a > >building that didn't have enough copper circuits. > > > >Dave > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
