Answer 7.7

The code rate is defined as the ratio of the k input bits to a block, divided by the n output bits of a block. Assuming that all of the additional bits in the coded stream are attributable to the block coder (that is, none are for framing, etc), then this must also be equal to the ratio of input bit rate to output bit rate. The code rate = 12000/20000 = 3/5.

The redundancy of the code is defined as (1 – code rate) = 2/5.