An apparatus including a computer for generating a time duration signal is proposed, intended in particular for controlling fuel metering or ignition processes in internal combustion engines, wherein the time duration signal is formed in accordance with the formulati=(R+K.multidot.Z)/fclwhere Z is the counting range of a counter associated with the computer, k is the number of counting processes, fcl is the counting frequency and R is a remainder value. In accordance with the above formula, the counter first counts downward from this remainder value R and then, for a desired number k of counting processes, runs through the total counting range. In the case of an 8-bit counter, for instance, this counting range value is 256.