Each sine wave signal output by the wheel speed sensor is conditioned and shaped to generate a square wave signal, which can be processed by the following methods in the subsequent circuit: (1) directly sent to the single chip microcomputer for T0 counting, with T 1 as the timer. Read the recorded value of T0 and calculate the wheel speed in every timing time of T 1; (2) Firstly, the square wave signal is converted by F/V, and then the wheel speed is obtained by A/D conversion of single chip microcomputer; (3) The square wave signal is sent to the external interrupt /INT0 pin of the single chip microcomputer, and set to the edge trigger mode. With T 1 as timer, the square wave signal is measured periodically, and the wheel speed is calculated. The wheel speed measured by the first method has a large error at low speed. Assuming the wheel speed is constant, the recorded value of T0 is read every T 1 timing time. Because of the position relationship between the head and the tooth tip when reading, the values read in the time of T 1i and T 1i+ 1 sometimes differ by 1. When the wheel speed is low, the T0 value recorded in T 1 timing time is relatively small. The second method can improve the measurement accuracy at low speed, but it increases the cost of hardware F/V and A/D conversion chips. The third method can effectively improve the measurement accuracy at low speed without increasing hardware overhead.