Spur detection in a sampled waveform in a mixed analog/digital system using the phase of the frequency response

An apparatus comprising:

• a target system configured to carry out converting an analog signal to a digital signal, wherein the target system includes a digital to analog converter (DAC) and analog to digital converter (ADC) pair;
• a computer processor;
• and
• a computer memory operatively coupled to the computer processor, the computer memory having computer program instructions that, when executed by the computer processor, perform:
• acquiring a sample waveform from the target system, including sampling the digital signal in a set of discrete, periodic, uniformly spaced samples as a time domain vector;
• applying FFT transforming the time domain vector into a frequency domain;
• analyzing the frequency domain response including calculating a phase response;
• and
• determining, based on comparing the phase response to a previously known clean phase profile without spurs, whether the sample waveform has spurs, including determining that the sample waveform has one or more spurs based on a determination that a phase profile value of the phase response is outside a phase deviation tolerance, wherein a spur indicates unaligned data having a delayed bit flip.

A computer program product including a non-transitory computer readable medium, the computer program product comprising computer program instructions that, when executed, cause a target system to carry out converting an analog signal to a digital signal, wherein the target system includes a digital to analog converter (DAC) and analog to digital converter (ADC) pair;

• wherein the computer program instructions, when executed, further cause a computer to carry out:
• acquiring a sample waveform of the digital signal including a set of discrete uniformly spaced samples from the target system, wherein the sample waveform is a time domain vector;
• applying FFT transforming the time domain vector into a frequency domain;
• analyzing the frequency domain response including calculating a phase response;
• and
• determining, based on comparing the phase response to a previously known clean phase profile without spurs, whether the sample waveform has spurs, including determining that the sample waveform has one or more spurs based on a determination that a phase profile value of the phase response is outside a phase deviation tolerance, wherein a spur indicates unaligned data having a delayed bit flip.