| 摘要 |
PURPOSE:To permit to determine the frequency of waveform shaping signal with high accuracy by a method wherein the masking frequency with respect to noise is changed in accordance with a primary coil voltage in the device in which the noise in the waveform shaped signal of the primary coil voltage generated in an ignition coil is being masked. CONSTITUTION:An ignition circuit 10 is equipped with a conduction control circuit 11, generating an ignition control signal necessary for the starting and finishing of conduction for the primary coil 21 of the ignition coil 20, and a transistor 12. In this case, a comparating means, comparing a preceeding waveform shaping signal with following waveform shaping signal and masking the following waveform shaping signal when the generating period of time of the following waveform shaping signal is shorter than a predetermined period of time, is equipped in a micro-computer 50, inputting the output signal of a waveform shaping circuit 40 shaping the waveform of a primary coil voltage Vi generated in the ignition coil 20 in order to utilize for the various kinds of control of the vehicle. On the other hand, a setting means, setting an elapsed time from the level change of the preceeding waveform shaping signal after releasing masking to the level change of the following waveform shaping signal as the period of following waveform shaping signal, is equipped in the device. |
