64 kbps comes about from sampling 8 bits at 8khz, 8x8000=64000
Bri
On Tue, 26 Feb 2002, John Neiberger wrote:
> This is OT, but the upper limit of human hearing is actually
> around 20KHz at best and usually drops to around 16KHz or so.
> If your upper limit starts to drop below that you'll start to
> notice that it's difficult to hear clearly. (Sorry, in my
> other life I'm a sound engineer and musician.)
>
> I've heard that the 4KHz limit is because there is a low-pass
> filter used for voice. I can't remember the exact reason, but
> that information plugged into the Nyquist theorem explains--as
> Priscilla mentions--why a DS0 is 64Kbps.
>
> Okay, time to do some serious studying once I'm through being
> lazy and drinking this coffee...
>
> John
>
> ---- On Tue, 26 Feb 2002, Priscilla Oppenheimer
> ([EMAIL PROTECTED]) wrote:
>
> > At 08:06 PM 2/26/02, Rafay wrote:
> > >How do you describe Sample Rate.?
> >
> > In what context? The term is sometimes used when describing
> the analog
> > to
> > digital process, for example when digitizing voice. Voice
> produces an
> > analog wave as your lungs and tongue press against the air.
> An analog
> > wave
> > has infinite possible values. Computers can't deal with
> infinity. They
> > work
> > with discreet numbers. The solution is to sample the analog
> voice many
> > times per second. Sampling means to take a snapshot.
> >
> > The sample rate is how often the analog wave is sampled.
> Nyquist showed
> > that you have to sample at twice the rate of the highest
> frequency that
> > may
> > occur in the original data. Most humans don't output (and
> can't hear)
> > anything about 4 KHz. So sample 8,000 times per second (8Khz)
> and the
> > result will be good enough. When using a sample rate of 8,000
> KHz, if
> > each
> > sample is saved in an 8-bit byte, the resulting data rate is
> 64 Kbps.
> > That's one DS0. Compression allows us to use a smaller data
> rate, with
> > some
> > loss in fidelity.
> >
> > Priscilla
> > ________________________
> >
> > Priscilla Oppenheimer
> > http://www.priscilla.com
> [EMAIL PROTECTED]
> >
> >
>
>
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