Landline is 0 to 4 KHz. (sampling rate 8 KHz and 8 bits for 64 kbs. Nyquist rate must be twice highest frequency). This is why a T1 is 1.544 MB/sec. 24 trunks times 64 kbs plus some overhead bits.)
What people don't know about cellphones is they're not sampling in the normal sense as we think of it as audiophiles but actually all the sounds are *synthesized* by vocoder. Your phone takes pitch, inflection, tone, etc. information and sends that information over the air and the vocoder merely re-synthesizes that information into sounds. That's why digital phones sound that way. They normally transmit 13 kbs at most. Average is much lower. It's done that way for capacity reasons. Much less information per user needs to be transmitted that way. The vocoders used to be, probably still are, set up for particular languages as well and that has an effect, if you're speaking another language than the country you're in speaks and has the phones set up for.
What people don't know about cellphones is they're not sampling in the normal sense as we think of it as audiophiles but actually all the sounds are *synthesized* by vocoder. Your phone takes pitch, inflection, tone, etc. information and sends that information over the air and the vocoder merely re-synthesizes that information into sounds. That's why digital phones sound that way. They normally transmit 13 kbs at most. Average is much lower. It's done that way for capacity reasons. Much less information per user needs to be transmitted that way. The vocoders used to be, probably still are, set up for particular languages as well and that has an effect, if you're speaking another language than the country you're in speaks and has the phones set up for.
