| 摘要 |
This system includes hysteresis comparison means (6, 9) whose output goes from a first state to a second state when the voltage of the ignition signal (SA) passes a predetermined high threshold and returns from the second state to the first state when the voltage of the ignition signal drops below a predetermined low threshold, a flip-flop circuit (8) triggered by the means of comparison (6, 9), and whose output delivers the said synchronous signal (SS), and a duration discriminator circuit (7) which only authorizes the switching over the flip-flop circuit (8) in response to the change in the output of the comparison means (6, 9) from the second state to the first state when the said output remains in the first state for a duration at least equal to a predetermined value. This invention may be used for measurement of the speed of an internal combustion engine. |
