Patent ID: 7173443

Claim:
A mixed signal test system for testing a semiconductor device having both an analog function and a digital function, comprising: a functional test unit for testing a digital function of a device under test (DUT) by providing a logic test pattern to the DUT and evaluating a response output of the DUT; an analog test unit for testing an analog function of the DUT by providing a test signal to the DUT and evaluating an analog output of the DUT; and a synchronous control unit for synchronizing operations between the functional test unit and the analog test unit; wherein the analog test unit, including: a digitizer for converting the analog output of the DUT into a digital signal wherein a wave form of the analog signal in a fixed time period T is repeated by a plurality of cycles and wherein each wave form is sampled at two or more sampling points within each-time period T by a sampling clock wherein the sampling clock for sampling the analog output is phase shifted by a predetermined amount for each cycle of the wave form; and an acquisition memory for storing the digital signal from the digitizer in addresses thereof specified by the phase shift in the sampling clock.