3-輸入 2-AND邏輯閘

module top;

wire A, B, C, OUT,OUT2;
system_clock #400 clock1(A);
system_clock #200 clock2(B);
system_clock #600 clock3(C);


and a1(OUT, A, B);
and a2(OUT2, OUT, C);

endmodule

module system_clock(clk);
parameter PERIOD=100;
output clk;
reg clk;

initial clk=0;

always
 begin
#(PERIOD/2) clk=~clk;
 end

always@(posedge clk)
 if($time>1000)$stop;

endmodule