| 摘要 |
A data processing apparatus is operable to map data symbols received from sub-carrier signals of Orthogonal Frequency Division Multiplexed (OFDM) symbols into an output data stream. The data processing apparatus includes an address generator, an interleaver memory and a controller. The controller is operable, when operating in accordance with an even interleaving process to read out from the interleaver memory a first set of the data symbols into the output data stream using addresses generated by the address generator, to write into the interleaver memory a second set of the data symbols received from the sub-carrier signals of an even OFDM symbol using the addresses generated by the address generator. The controller is operable in accordance with an odd interleaving process, to read out from the interleaver memory a first set of the data symbols into the output data stream using read addresses determined in accordance with a sequential order of the first set of data symbols, and to write into the interleaver memory a second set of the data symbols received from the sub-carrier signals of an odd OFDM symbol at write addresses determined in accordance with a sequential order of the first set of input data symbols, such that while data symbols from the first set are being read from locations in the interleaver memory, input data symbols from the second set can be written to the locations just read from. The number of the sub-carriers which are available from a previous OFDM symbol is different from the number of the sub-carriers which are available from a current OFDM symbol, and the controller is operable to determine before reading out the first data symbols from the interleaver memory, whether the read address is valid for the previous OFDM symbol, and to determine before writing the second data symbols into the interleaver memory, whether the write address is valid for the current OFDM symbol. Application can be found with DVB Cable 2, which can provide substantially four thousand carriers. |
