Patent ID: 7919968

Claim:
A method of analyzing distortion comprising: determining, via a sampling circuit that receives an analog signal under test from a circuit under test, an amplitude and a relative phase of the analog signal under test; receiving the analog signal under test at a sampling circuit comprising an analog-to-digital converter to generate a digital signal under test based on the analog signal under test; generating an analog reference signal based, at least in part, upon the amplitude and the relative phase information contained in the digital signal under test received from the sampling circuit, the analog reference signal generated by a signal generator circuit comprising a digital to analog conversion circuit, wherein the signal generator is further configured to remove all or a portion of the distortion present within the digital signal under test; combining, via a combining circuit, the analog reference signal from the signal generator with the analog signal under test to generate a residual signal indicative of a distortion within the signal under test; and measuring the residual signal, wherein measuring the residual signal includes providing the residual signal to the analog-to-digital converter.