Using a sigma-delta modulator as a test vehicle for embedded mixed-signal test

An embedded mixed-signal test system that utilises a sigma-delta modulator as a vehicle to test analogue and digital embedded circuits is presented. A self-characterisation routine and simulation results relating to a behavioural sigma-delta model of the system will show how correlation analysis techniques can be used to evaluate the impulse response of a linear module under test (MUT) and how frequency and amplitude signal faults can be detected and accurately measured.