network11:
A "x12_3"
= L 0.0
A L 0.0
AN "fmi_X12_3"
= "fm_X12_3"
A L 0.0
BLD 102
= "fmi_X12_3"

network14:
A "un"
= L 0.0
A L 0.0
AN "x12_4"
A "fdi_X12_4"
= "fd_X12_4"
A L 0.0
A "x12_4"
= "fdi_X12_4"
不理解的地方是：这两个network13 :Rising edge step X12_3
network14 :Trailing edge step X12_4
它们这样编程的目的是什么呢？
这段程序怎么理解？