Viterbi decoding apparatus, method for controlling slip state of convolutional code in viterbi decoding apparatus, and slip state control apparatus

摘要

In a viterbi decoding apparatus, a depuncture circuit is always synchronized with the input of a correct convolutional code irrespective of the degree of noise in the transmission path of the convolutional code. A comparator (4) makes a comparison of error numbers of slip states 1 through N stored in registers (R1) through (RN) of the register group (2), respectively, to detect a register (Rk) (k=either of 1 through N) storing the minimum error number thereby to output a minimum slip state (MINSLIP) indicating the slip state k to a slip state determination portion (5). The slip state determination portion (5) determines the minimum slip state (MINSLIP) to be a determined slip state (DSLIP) when the minimum slip state (MINSLIP) continuously indicates the same slip state M times.