i wnat measure time priod that start when signal 1 cross constant value and finish when signal 2 cross zero (see picture)

in another word its a workflow that measure time priod that start when signal 1 cross constant value and finish when signal 2 cross zero and again start measurement. so what block do you propose to use in simulink ?

[Walter Roberson]

Is the constant value greater than 0 or less than 0 ? It might make a difference to how easy it is to write the expression.

[mohsen tawakoli]

the value is optional and must be 0<=teta<=360

and its can be zero