What would be the fastest dial-up access speed if phone systems had 144 dB of dynamic range?
in [DSP]
|
Prev: Receiver sensitivity calculation - WiMax
Next: What would be the fastest dial-up access speed if phone systemshad 144 dB of dynamic range?
From: Green Xenon on 16 Nov 2009 15:11 Hi: The following is not a homework question. It is a question of my curiosity. Currently dial up internet access has a maximum theoretical speed of 64 kbps. This is due in part to the 48 dB dynamic range of telephone systems. If telephones systems are updated so that they have a dynamic range of 144 dB instead of 48 dB, what will be the maximum theoretical speed of dial-up internet access? Thanks
From: Randy Yates on 16 Nov 2009 15:19 "Green Xenon" <green_xenon1(a)yahoo.com> writes: > Hi: > > The following is not a homework question. It is a question of my > curiosity. > > Currently dial up internet access has a maximum theoretical speed of 64 > kbps. This is due in part to the 48 dB dynamic range of telephone systems. > > If telephones systems are updated so that they have a dynamic range of 144 > dB instead of 48 dB, what will be the maximum theoretical speed of dial-up > internet access? The easy answer is provided by the capacity formula C = W * log_2(1+P/N) = 4000 * 144/log_10(2) = 1.2 Mb/s -- Randy Yates % "Midnight, on the water... Digital Signal Labs % I saw... the ocean's daughter." mailto://yates(a)ieee.org % 'Can't Get It Out Of My Head' http://www.digitalsignallabs.com % *El Dorado*, Electric Light Orchestra
From: Randy Yates on 16 Nov 2009 15:20 Randy Yates <yates(a)ieee.org> writes: > [...] Doh! Just realized this is that weird dude. Sorry I responded! -- Randy Yates % "Ticket to the moon, flight leaves here today Digital Signal Labs % from Satellite 2" mailto://yates(a)ieee.org % 'Ticket To The Moon' http://www.digitalsignallabs.com % *Time*, Electric Light Orchestra
From: Randy Yates on 16 Nov 2009 17:15 Tim Wescott <tim(a)seemywebsite.com> writes: > On Mon, 16 Nov 2009 15:19:58 -0500, Randy Yates wrote: > >> "Green Xenon" <green_xenon1(a)yahoo.com> writes: >> >>> Hi: >>> >>> The following is not a homework question. It is a question of my >>> curiosity. >>> >>> Currently dial up internet access has a maximum theoretical speed of 64 >>> kbps. This is due in part to the 48 dB dynamic range of telephone >>> systems. >>> >>> If telephones systems are updated so that they have a dynamic range of >>> 144 dB instead of 48 dB, what will be the maximum theoretical speed of >>> dial-up internet access? >> >> The easy answer is provided by the capacity formula >> >> C = W * log_2(1+P/N) >> = 4000 * 144/log_10(2) >> = 1.2 Mb/s > > ... and is, unfortunately, wrong. That's right, Tim. Arithmetic error! C = W * log_2(1+P/N) = 4000 * 14.4/log_10(2) = 191,343 b/s > [...] This other stuff is erudite drivel that basically depends on assumptions. Seeing as how this guy is prone to wild questions, I see no reason to laboriously debate assumptions when I've already honored the question too much just providing a response. -- Randy Yates % "I met someone who looks alot like you, Digital Signal Labs % she does the things you do, mailto://yates(a)ieee.org % but she is an IBM." http://www.digitalsignallabs.com % 'Yours Truly, 2095', *Time*, ELO
From: Green Xenon on 16 Nov 2009 20:35
>"Green Xenon" <green_xenon1(a)yahoo.com> writes: > >> Hi: >> >> The following is not a homework question. It is a question of my >> curiosity. >> >> Currently dial up internet access has a maximum theoretical speed of 64 >> kbps. This is due in part to the 48 dB dynamic range of telephone systems. >> >> If telephones systems are updated so that they have a dynamic range of 144 >> dB instead of 48 dB, what will be the maximum theoretical speed of dial-up >> internet access? > >The easy answer is provided by the capacity formula > > C = W * log_2(1+P/N) > = 4000 * 144/log_10(2) > = 1.2 Mb/s What do "P" and "N" stand for? |