Method and apparatus for digital sample rate conversion. A mixed signal tester employing digital sample rate conversion is also disclosed. According to the invention, variable phase jitter is introduced into an input digital signal to produce an intermediate signal at a second sampling rate. The intermediate signal is then low pass filtered to produce the output signal. This technique is used in a mixed signal tester where one period of a stimulus signal is stored in a digital memory. The frequency of the analog stimulus signal is dictated by the rate at which the digital signal is retrieved from the memory. Sample rate conversion is used to convert the signal retrieved from memory, regardless of the rate at which it was retrieved, to the sampling rate for which a digital to analog converter has been calibrated.