METHOD AND DEVICE FOR CONTROLLING KEYING RATIO OF PULSE VOLTAGE HAVING VARIABLE FREQUENCY

To permit real-time counting of pulses representative of operating parameters of a moving body, for example in an internal combustion engine to control the ignition timing as a function of speed and other parameters in which, upon increase in speed of the engine, the ignition pulses follow each other rapidly and to permit sufficient current flow through the ignition coil for proper ignition, pulse sequences derived from the engine, for example as a function of speed, are converted into a higher frequency and the original pulses and the higher frequency are supplied to the counter as pulse trains so that the counter will reach the appropriate count state for which the ignition angle is to be computed at a time sufficiently in advance of the triggering of the ignition current, so that the time available for flow of ignition current will be increased, even at high engine speeds. Two pulse trains, differing in frequency and length, are applied to the counter, the counter being set for each triggering or ignition pulse to a predetermined value by a count angle computer stage, the pulse duration and cycling duration of the pulse voltage being determined by the counting time below and above a certain count state of the counter.