Re: Radios for higher speeds,
- To: email@example.com
- Subject: Re: Radios for higher speeds,
- From: Phil Karn <firstname.lastname@example.org>
- Date: Thu, 9 Feb 1995 19:27:32 -0800
- Cc: email@example.com
- In-reply-to: <3898FDF6EB5@voreas.ee.duth.gr> (SALKI@voreas.ee.duth.gr)
>Why it is nessesary to have a 15KHz bandwidth for 9.6Kb, when in the wireline
>case it is sufficient a 2.4KHz for 28.8Kb ??
There's a fundamental tradeoff between bandwidth and S/N ratio. On a phone
line where you have high S/N, you can use higher-order modulation schemes
to get many bits/sec per Hz.
You *could* apply these same schemes to radio channels but, as Richard
Nixon once said, "that would be wrong". Modulation schemes that give many
bits/sec/Hz are inherently more sensitive to noise and interference, which
is much more of a problem on radio than on phone lines.