VARIABLE LENGTH CODE WORD DECODER FOR USE IN DIGITAL COMMUNICATION SYSTEMS

摘要

Apparatus (10) is provided for decoding variable length code words to recover transform coefficients, such as DCT transform coefficients provided by a high definition television encoder. A first category of the code words has a length of no more than n bits. A second category has a length of greater than n bits. A feedback ROM (22) is used to decode the code words. Code words from the first category are processed by directly addressing a lookup table (80) in the ROM (22). Code words from the second category are processed using multiple passes through the ROM (22), wherein a portion of the data output during a prior pass is fed back (90) to address the memory during a subsequent pass.