输入信号A、B为相位差90°的方波信号。当A导前B 90°时，Uo1有输出，Uo2无输出，当B导前A 90°时，Uo1无输出，Uo2有输出，实现辨向。 -Input signals A, B phase difference 90 ° for the square wave signal. When A Introduction B 90 °, when the former, Uo1 have output, Uo2 no output, when the B I. A 90 ° when the former, Uo1 no output, Uo2 are output, to achieve identified.