| 摘要 |
PURPOSE:To eliminate a flicker of display during a constant-speed run and answer delay during acceleration and deceleration by displaying the mean movement value of a car speed signal when the variation rate of the signal is below a certain value, and displaying the signal as it is when the rate is above a certain value. CONSTITUTION:A car speed sensor 1 outputs car speed pulses whose number is in proportion to the speed of a car. A car speed counter 4 counts the car speed pulses inputted through a gate 2 which is opened and closed by the output of an oscillator 3, and outputs the result to a mean value circuit 5 and a car speed register 6. The mean value circuit 5 input (n) pieces of the count values to find their mean value. The car speed register 6, on the other hand, latches the car speed every time the count value is inputted. Then, an acceleration discriminating circuit 7 compares both the values to select the output of the mean value circuit 5 during a stable run, namely, when the variation rate of the car speed is below a certain value, or the output of the car speed register 6 during acceleration or deceleration, namely, when the rate is above the certain value, thereby displaying the selected output on a display device 9. |
