17 Aug 2004
CS 5244: Self-Study
2
Fixed and variable bit widths
¡To encode
English text, we need 26 lower case letters,
26 upper case letters, and a handful of punctuation
¡We
can get by with 64 characters (6 bits) in all
¡Each
character is therefore 6 bits wide
¡We
can do better, provided:
lSome
characters are more frequent than others
lCharacters
may be different bit widths, so that for example, e use only one or
two bits, while x uses several
lWe
have a way of decoding the bit stream
¡Must
tell where each character begins and ends