Computers as Components, 2nd Edition

136 CHAPTER 3 CPUs

Once the code has been constructed, which in many applications is done off-line,

the codes can be stored in a table for encoding. This makes encoding simple, but clearly

the encoded bit rate can vary significantly depending on the input character sequence.

On the decoding side, since we do not know a priori the length of a character’s bit sequence,

the computation time required to decode a character can vary significantly.

The data compressor as discussed above is not a complete system, but we can

create at least a partial requirements list for the module as seen below. We used the

abbreviation N/A for not applicable to describe some ...