Patent ID: 8289569

Claim:
An encoder signal processor which processes a pulsed encoder signal output from an encoder in accordance with a travel distance of an object to be detected, comprising: an increasing and decreasing wave generating unit that generates an increasing and decreasing wave, which increases when the encoder signal is at one of a high level and a low level and decreases when the encoder signal is at the other level, based on the encoder signal output from the encoder; an intermediate pulse signal generating unit that generates a binarized intermediate pulse signal, of which logic is inverted for every predetermined timing in an increasing period and every predetermined timing in a decreasing period of the increasing and decreasing wave, based on the increasing and decreasing wave generated by the increasing and decreasing wave generating unit; and a multiplied pulse signal generating unit that generates a multiplied pulse signal, which is a signal obtained by multiplying the encoder signal by 2, by performing exclusive-OR operation between the encoder signal output from the encoder and the intermediate pulse signal generated by the intermediate pulse signal generating unit.