WHEEL VELOCITY DETECTING APPARATUS

A wheel velocity detecting apparatus capable of accurately detecting a very low velocity (10 km/h or lower). A frequency signal corresponding to the rotational speed of a wheel is detected by a rotary sensor and converted by an A/D converter into a digital signal. A processor processes the digital sensor signal to detect a wheel velocity. Specifically, when the sensor signal is expressed by y=f(.omega.)cos(.omega.t), the difference between the output derived by squaring the signal and the output derived by multiplying a time-differentiated version of the signal by a time-integrated version of the signal is calculated to finally derive f.sup.2 (.omega.). Since f (.omega.) is uniquely determined in accordance with the rotational speed (.omega.), the wheel velocity can be accurately detected even in a very low velocity range.