| 摘要 |
PROBLEM TO BE SOLVED: To provide a trellis de-mapper with a function of de-mapping 8-PSK, 16, 32, 64, 128, 256 QAM (quadrature amplitude modulation) trellis codes. SOLUTION: A trellis de-mapper 310 is provided with an I channel RAM 400, a Q channel RAM 402, a re-mapper RAM 404, an 8-PSK de-mapper logic means 406 and an MUX 408. Each RAM has a lookup table, which is programmed selectively for each QAM code. Each of the I channel RAM 400 and the Q channel RAM 402 has a storage capacity of 768 bits, and when a GAM trellis code being an even number multiple of 2 (that is, 16, 64 or 256) is selected, each RAM transfers each output directly via the MUX (multiplexer) as a trellis de-mapper output in response to the selection. |
