The timing simulation

which can describe the logical behaviors as well as the time relation between the behaviors occurring in the circuit

is an efficient approach to analyse logical circuits. There are some troubles in timing analysis by using two-valued and three-valued systems due to their own restrictions. A model on the basis of six-valued logic system for timing analysis is presented in this paper. The model and the simulation algorithm are detailed and the comparison between the six-valued model and other models in timing simulation are given. The response of the system is obtained by means of the time matched simulation algorithm. The program for six-valued timing simulation written in FORTRAN-4 which is developed as an important part in LOCAS system has been executed on PDP-11/34 computer

and the results for some sample circuits are found satisfactory.