| 摘要 |
A cable transmitter (100) supports a number of low density parity check (LDPC,105) coding rates, e.g., 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9 and 9/10; and supports a number of quadrature amplitude modulation (QAM,115) schemes, e.g., 4-QAM, 16-QAM, 64-QAM, 256-QAM, 1024-QAM. For each m 2 -QAM scheme, a uniform m -PAM symbol constellation is used for the one axis (115-1) of the QAM modulation and a non-uniform m -PAM symbol constellation is used for the other axis (115-2) of the QAM modulation. |
