Patent ID: 7221148

Claim:
A wheel speed sensor assembly comprising a rotary member configured to be fixedly mounted on a wheel so as to rotate together with the wheel, said rotary member producing fluctuations in magnetic field when said rotary member rotates together with the wheel, and a wheel speed sensor comprising two magnetoelectric devices for picking up said fluctuations in magnetic field and producing waveforms corresponding to said fluctuations, and a signal processing unit for producing a differential waveform from said waveforms produced by said two magnetoelectric devices, and producing block pulses from said differential waveform based on upper and lower thresholds, said differential waveform comprising first portions overshooting said upper threshold, second portions overshooting said upper threshold and arranged alternately with said first portions, third portions undershooting said lower threshold and each provided between an adjacent pair of said first and second portions, each of said third portions connecting with the adjacent pair of said first and second portions through fourth and fifth stepped portions, respectively.