WAVEFORM SHAPING CIRCUIT OF ROTARY ENCODER

摘要

PURPOSE:To suppress the fluctuation in rotary speed due to the fluctuation in amplitude, by providing a circuit, which makes the amplitude of a sinusoidal wave or pseudo-sinusoidal wave of a rotary encoder constant. CONSTITUTION:A signal As is inputted to a full-wave rectifier circuit 3, and an absolute value signal ¦As¦ is obtained. The signal ¦As¦ is inputted to peak detectors 4 and 5. The output of the detector 4 is connected to a divisor input Z of a dividing circuit 8 through a switch circuit 6. The output of the detector 5 is connected to the divisor input Z through a switch circuit 7. Meanwhile, the signal As is compared with a reference potential by a comparator 10, and a positive or negative constant voltage As1 is outputted. A circuit 12 and a circuit 13 are reset-signal generating circuits, which generate reset pulses RES1 and RES2. The pulses reset the detectors 4 and 5 during the periods from the zero point and the next zero points of the signal As to the peaks in the later half cycles of the signal As, respectively. When the signal As is divided by z, a sinusoidal wave or a pseudo-sinusoidal wave output Aso, which has the same frequency as the signal As and a constant amplitude, can be obtained at an output terminal 2.