| 摘要 |
<p>Apparatus and methods in both modem transmitters (50) and receivers (130) are provided for accommodating secondary channel data without disturbing the trellis encoding, mapping, and Viterbi decoding of primary channel data, and without disturbing distribution preserving Tomlinson precoding and decoding of the primary channel data. In order to accommodate the secondary channel data, the secondary channel data are used to make quadrant decisions in a mapper (60), and concurrently therewith, dummy data or tertiary channel data corresponding in time with the secondary channel data are provided to the trellis encoder (55) so that the continuous working of the trellis encoder (55) can be maintained. In order to guarantee proper working of the trellis encoder (55), the secondary channel constellation points within a quadrant are clustered together and far from the quadrant boundaries.</p> |
