Error propagation significance of Viterbi decoding of modal and non-modal ternary line codes

The state machine representation of ternary line codes helped making use of the Viterbi decoder (VD), which is considered to be the maximum likelihood decoding algorithm. Viterbi decoding algorithm provides 2 dB gain between soft and hard decisions decoding. Since Viterbi decoding algorithm is usually designed for linear convolutional codes, we expect error propagation when applied to ternary line codes. These codes have gain the trellis structure from their state machine representation.