Subject: Re: questions ?

From: Christopher Rose <crose>
Date: Mon, 14 Apr 97 19:47:10 EDT

1) and indicator function is 1 when the "indicated condition"
is true and zero otherwise.

2) A sequence of codes is what is meant.  You're looking
for codes which may vary with n.  That is, there's a different
code for each n.  HOwever, the coding procedure (typical coding)
does not change.

3) FIrst order in exponent means to first order in n.

4) x_i(w)^2 is the i^th power level used
in sequence of n channel uses.  Remember that for continuous
channels we're using continous levels as opposed to binary symbols.
Thus, the example on page 79, which is for discrete sources
is not applicable.  Think of it this way.  For the continuous
channel we're sending a signal during a channel use (say on an interval
(0,T)).  We can sent a large signal (with large power) and correspondingly
large x_i or we can send a smaller signal.  That is, we're sending
actual levels over the channel.

The only place where discreteness comes in is that we're
using sequences of these powers to code discrete messages.
Specifically, we have 2^(nR) messages which we're trying to code
with a sequence of n levels (x_i).

Cheers