Prolly a function of the A/D and D/A in the PCI card. If Brother Nyquist really rules, then the designers of that card have the sampling rate and dynamic range set properly. Me thinks 3.4 kHz BW would be a piece of cake yet would recommend testing prior to making a claim.
/jim -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rob Lockhart Sent: Wednesday, January 21, 2004 11:05 AM To: Triangle Linux Users Group discussion list Subject: Re: [TriLUG] IP Phone Jon I meant to ask you a question at the last meeting, but it is perhaps a bit technical in nature. How does the VoIP system handle POTS sample rate recovery and NTR for sampling over an IP network without such capabilities? Otherwise, I would assume that things like Tivos and such (you have to have a land line for unhacked DirecTivo) that require POTS modem access for pay-per-view and other such things would not work reliably (due to a high connect rate causing a high bit-per-symbol allocation) the QAM signalling getting screwed up by the irregularly-arriving packets. I could even imagine that, say, network latency being very low and consistent during training, and then a few seconds later having different latency (or jitter) characteristics than during training, that this may cause the CPE modem to train up at a higher rate than the VoIP system can compensate for, thus it may cause the narrowband modem link to drop and attempt retrain. Just curious.... Of course this is very hard to detect with your ear and the right decoding/encoding techniques but I doubt they'll work very well for a 33.6kbps or higher connect rate (due to the density of the constellation). Regards, -Rob -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc
