JPS5512239A - Wave-form switching apparatus - Google Patents

Abstract

PURPOSE:To prevent misfire by switching wave-form at the time point when specific conditions due to the combination of phases of signals are settled, irrespective of the timing of generation of wave-form switching instruction signal from outside, in an ignition timing switching apparatus. CONSTITUTION:When level signals are generated from an ignition generating time signal source outside, a transistor 115 conducts. But, as the outputs of the first and the second signal generators 1a and 1b are of 0 level, the transistor 62 of a first gate 6O is in the nonconducting state, and the transistor 72 of the second gate 70 conducts, and only the output signal of the first signal generator 1a is transmitted to an output amplifying circuit 30. At the next time point, when ignition timing signals of both the first and the second becomes of 1 level, the second ignition time signal is transmitted to the output amplifying circuit 30. This state continues even when the signal of an ignition time signal generator 5 returns to 0 level, and continues until two ignition signals become of 1 level, and thus, the smooth switching of wave form is obtained and misfire is prevented.