Expert: Cezar L. Palconet Date: 11/1/2007 Subject: 1 Gbps on dial-up modems -- physically-possible?
Question Hi:
I might have sent you this question before. I so, I apologize profusely for the repitition. Something was wrong with my browser making me unable to tell whether I sent you this question.
Is it physically possible to for dial-up internet connection to reach a speed of 1 Gbps by using a baud of 1-symbol-per-second [to conserve bandwidth] but 1-billion-bits-per-symbol?
Each symbol carries a billion bits bits but with only 1 baud.
bps = baud X number of bits per baud.
Is this physically-possible?
Thanks,
Green
Answer What limits the bandwidth on twisted pair is the line insertion losses,
With a typical house wiring for telephone in a dial up connection, line losses in 400 Mhz. will be enormous, much so with a 1Ghz. even with the best cable the usable limits is around 400 Mhz.
It is not the bps to a word ratios that determine losses in a cable transmission it is the frequency.
Bps per word is only valid on the modulator, and not the transmission line.
