Highly efficient Viterbi codecs are available for purchase. They are implemented in hand-coded Assembly language for Pentium processors and run under the Windows operating system. Some technical details are given below; additional information regarding licensing terms and fees may be obtained via e-mail (fec-info (at) crc.ca).

Viterbi Codec Library (vcdll.dll)

• Applies to binary convolutional codes
• Constraint lengths K=7 through K=17
• Nominal code rate of 1/2
  • Higher code rates are achieved with external puncturing
• Trellis termination: zero-flushed or tail-biting
• Information throughput (decoding speed):
  • Greater than 6 Mbps for constraint length K=7 on a 3.4 GHz Pentium D processor
  • Throughputs for higher constraint lengths are approximately inversely proportional to the number of states
• Block sizes from 16 information bits up to the limits of system memory

Simulation software (vcsim.exe) that allows the measurement of performance in additive white Gaussian noise (AWGN) is also included.