| 摘要 |
<p>To enable binary data to be differentially encoded into symbols (waves) for transmission, the data is applied in n-bit data-words to produce symbols which, when displayed in a phasor-diagram, are in three groups in three 120° phase sectors respectively, (SECTOR 1, SECTOR 2, SECTOR 3), the number and dispositions of the symbols in the three sectors being the same. The encoding is such that, depending upon the data-word to be transmitted the sector in which a symbol is produced is rotated by 0°, 120° or 240° relative to the next preceding sector containing a symbol. In some embodiments one of the 2n possible different data-words is applied to produce an absolute symbol of zero amplitude. At a receiver the received symbols are decoded having regard to the 0°, 120° and 240° differential sector-rotations.</p> |
