| 摘要 |
PURPOSE:To minimize difference between actual speed of a vehicle and the indicated speed, by preventing transition of hysteresis curve by fixing low-level bit which is not shown on an indicator of signal to be put into a hysteresis processing circuit from an indication register. CONSTITUTION:A vehicle speed pulse 100 which is generated in accordance with rotation of wheel and in proportion to a vehicle speed is put into a vehicle speed counter 12 and counted for a constant time T. At the same time, a hysteresis processing circuit 16 seeks difference between an output signal 102 of the vehicle speed counter 12 and a content 103 of an indication register 14, and in case if thus sought difference does not exceed a prescribed value set by the hysteresis processing circuit 16, the content of the register 14 is not changed unnecessarily, and an indication value of an indicator 18 is maintained at a constant value. And, at that time, the lowermost bit of the signal 103 to be put into the hysteresis processing circuit 16 by a setting unit 29 is fixed to ''1'' or ''0'' so as to prevent transition of the hysteresis curve by variation of the lowermost bit. It is possible, by using such a mechanism, to minimize difference between an actual vehicle speed and the indicated speed. |
