Re: oversampling
On Sat, 3 Jan 1998, KC5TJA wrote:
> > lots of DSP sofware. 6 bit for A/D I/O should suffice.
>
> If you want any degree of error recovery, and/or high throughput, for
> anything above 4800 baud, you need at least a 12-bit A/D converter.
All modern CD players have 1-bit D/A converters. The key word is
oversampling (with analog low-pass filtering at the end).
As to the A/D, remember that the spectrum of the phone signal is band
limited. So oversampling is again the key word.
Well, that one helluva DSP to deal with it :-)
But, as Jeff will say, you don't need to generate video on the second x21,
so things might be manageable.
Who knows. Unless one does the calculations, one cannot be sure.
The point was, the (retail) price of an external modem is $20-$30 more
than that of an internal, and this obviously does not have anything to do
with DSP power and A/D converters (apart from the winmodem breed :-)
And the beast, packaged and delivered is $85. Not $50.
Once again, who knows,
--
Penio Penev <Penev@pisa.Rockefeller.edu> 1-212-327-7423
