Abstract: Time-critical events are localized within a clocked electronic circuit without requiring cyclical operation By way of measuring at the outputs of the circuit, the limit frequency of the circuit is identified. A test pattern sequence is then applied to this circuit. The number n of that test pattern at which errors are perceived at the outputs is identified, in particular with a clock frequency higher than the identified limit frequency of the circuit. The test patterns having the numbers n-m are applied to the circuit with a clock frequency greater than the identified limit frequency of the circuit and the remaining n test patterns are applied to the circuit with a clock frequency lower than the identified limit frequency of the circuit, being applied thereto in succession step-by-step with m=1,2,3 . . . in at least one run of n test patterns.