Analog circuit testing and test pattern generation

Test vectors for structural testing of an analog circuit are selected by first selecting an initial set of test input vectors for the analog circuit. A set of faults is selected, comprising faults that each correspond to a respective node in the analog circuit and corresponding fault voltage value for that node. A measure of overlap is computed between probability distributions of test output signal values for the analog circuit in response to the test input vectors in the presence and absence of each of the faults from said set of faults respectively, as a function of estimated statistical spread of component and/or process parameter values in the analog circuit.; Test input vectors are selected from the initial set of test input vectors for use in testing on the basis of whether the measure of overlap for at least one if the faults is below a threshold value in response to the selected test input vector under control of the test selection computer