利用脉冲计数产生一个脉宽可调的脉冲，然后作为使能信号送给计数器。测试在具有不同相位时钟下的计数效果，太过设置计数频率，可发现不同相位的时钟计数差别，经验证-Pulse counting to generate a pulse width adjustable pulse, and then as an enabling signal is sent to the counter. Test in a different phase clock count, too set the count f