how to use Simulink block diagram for viterbi (..,tran_func)?

Hi,

anyone used Simulink block diagram to generate
tran_func for matlab function viterbi(code, tran_func)?

SIM2TRAN Converts a Simulink block diagram to convolution code transfer function.
TRAN_FUNC = SIM2TRAN(SIM_FILE) reads in a Simulink block diagram file specified in the string SIM_FILE.

How to build this Simulink block diagram? I have no idea from SIM2TRAN help. Please help if anyone used it.

Thanks a lot,

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