| 摘要 |
PURPOSE:To enable the inexpensive detection of a speed signal, by a method wherein differentiation circuits for respectively differentiating two-phase output signals of a rotary encoder, a circuit for imparting the absolute values of said output signals and the adder thereof are provided and the output signals of the encoder are detected as a speed signal. CONSTITUTION:Two-phase outputs of a rotary encoder are sent to differentiation circuits 7, 8 and changed in the amplitudes thereof in proportion to the rotary number of the encoder as well as converted to digital signals by wave form shaping devices 13, 14. Absolute value circuits 9, 10 take out the absolute values of the output signals of the differentiation circuits 7, 8 and an adder 11 applies the sum of outputs of the absolute value circuits 9, 10 while the outputs of said circuits 9, 10 are reversed by a reversal amplifier 12. FF15 judges the rotary direction of the rotary encoder by the digital signals of the wave form shaping devices 13, 14. An analogue SW16 outputs the output signals of the adder 11 and the reversal amplifier 12 while changing over the same by the output signal of FF15 and the changed-over signals are outputted through a filter 17. An output wave form is changed in the output voltage in proportion to the rotary number of the encoder and a code is different by the rotary direction. As a result, a speed signal can be detected. |
