Rotational speed signal error detection method for anti-slip or anti-lock regulation system of vehicle, involves detecting speed change based on specific condition involving pulse width of falling pulses of measurement signal

摘要

Pulse sequence (1) having rising pulses (2) of width (teven) and falling pulses (6) of width (todd) are output by a wheel speed measurement magnetic pole. Speed change is detected, when the conditions t(n+1) less than X * t(n+3) and t(n+3) less than X * t(n+1) are not satisfied, where X is the duty factor which is set preferably to 2. When the condition t(n+5) greater than X * t(n+3) is satisfied, signal drop-out is detected. Measurement poles arranged at periphery of magnetic wheel, output a pulse sequence (1) having rising pulses and falling pulses. When falling pulse continues for more than specific period, signal drop-out is detected.