A data encoding system includes a modifier, an encoder, and a feedback. The modifier
receives a first data stream and modifies the first data stream so as to provide
a second data stream. The encoder encodes the second data stream in order to provide
an output. At least a portion of the output has predetermined symbol values. A
feedback from the encoder to the modifier provides encoder states to the modifier.
The modifier modifies the first data stream based on the encoder states so as to
facilitate the encoder in providing the portion of the output having the predetermined
symbol values. A receiver receives a signal based on the output and decodes the signal.
