使用模为2N+1的计数器,让输出时钟在X-1(X在0到2N-1之间)和2N时各翻转一次,则可得到奇数分频器,但是占空比并不是50 -The use of modulo 2N+1 counter, let the output clock in the X-1 (X between 0 and 2N-1) and 2N of the turning once, then can get the odd divider, but the duty ratio is not 50