A low bit-rate speech codec has been developed. The speech coder employs a PCELP (CELP with pulse codebook) algorithm, which uses a pulse-train excitation codebook to enhance the quality of voiced speech. The computational complexity for the pulse codebook search is greatly reduced by using truncated impulse responses of a weighted synthesis filter. An improved Viterbi decoding method using error detecting code information instead of tail bits has also been developed to increase the effective error-correction coding rate. A 5.6 kb/s speech codec has been implemented by incorporating the PCELP speech coding algorithm with the improved Viterbi decoding. Formal listening tests show that the synthetic speech quality of this codec is equivalent to that of 5.4-bit /spl mu/-law PCM in the absence of channel errors.>

A new LSI artwork analysis and processing system, called EMAP, is described with algorithms, a database schema and applications. EMAP provides the designer with the artwork verification and processing tools which include mask artwork processing, geometrical design rule checking, connectivity analysis and electrical circuit parameter calculation. The circuit connectivity data derived from the mask artwork data is used for input to a logic simulator, a timing simulator, a circuit simulator and a circuit schematic generator.