HUT Communications Lab. / Timo O. Korhonen
36
PCM with channel noise
nRandom noise added into code
words causes some code words to change their valuesnEffect
on signal error depends where it falls in the code word: Errors in the
most significant bits (MSB) are a bigger problem than errors in the
LSBnThe
m:th bit distinguishes between quantum levels spaced by 2m times the step height 2/q. Therefore the
error on the m:th bit shifts the decoded level by
and for the whole code word bit-error probability Pe
nThe
average channel noise power for a single bit at the decoded signal is
therefore
and for the whole code word bit-error probability Pe
