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

Patent metadata

Field	Value
Publication number	US-12523680-B2
Application number	US-201916593471-A
Country	US
Kind code	B2
Filing date	Oct 4, 2019
Priority date	Oct 4, 2019
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

Abstract

Method, apparatus and computer program product for spur detection in a sampled waveform in a mixed analog/digital system using the phase of the frequency response comprising acquiring a sample waveform including a set of discrete uniformly spaced samples from a target system, wherein the sample waveform is a time domain vector; applying FFT transforming the time domain vector into the frequency domain; analyzing the frequency domain response including calculating the phase response; and determining whether the sample waveform has spurs including comparing the phase response to a clean phase profile including determining that the phase response having a phase profile value outside a phase deviation tolerance has one or more spurs and determining that the phase response having a phase profile value inside the phase deviation tolerance has no spurs, wherein a spur indicates unaligned data having a delayed bit flip.

First claim

What is claimed is:

1 . A method comprising:
converting, by a target system, 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; by program instructions on a computing device,
acquiring, from the digital signal, a sample waveform 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.

2 . The method of claim 1 , wherein determining whether the sample waveform has spurs includes:
determining that the sample waveform has no spurs when the phase profile value of the phase response is inside the phase deviation tolerance.

3 . The method of claim 1 , wherein the DAC and ADC pair in the target system are in a loopback connection.

4 . The method of claim 3 , wherein the sample waveform is acquired from an output of the DAC, and wherein a signal associated with the known clean phase profile without spurs is different from the digital signal associated with the phase response.

5 . The method of claim 3 , wherein the sample waveform is acquired from an output of the ADC.

6 . The method of claim 1 , wherein the sample waveform is acquired from an output of the DAC.

7 . 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.

8 . The apparatus of claim 7 , wherein determining whether the sample waveform has spurs includes:
determining that the sample waveform has no spurs when the phase profile value of the phase response is inside the phase deviation tolerance.

9 . The apparatus of claim 7 , wherein the DAC and ADC pair in the target system are in a loopback connection.

10 . The apparatus of claim 9 , wherein the sample waveform is acquired from an output of the DAC.

11 . The apparatus of claim 9 , wherein the sample waveform is acquired from an output of the ADC.

12 . The apparatus of claim 7 , wherein a signal associated with the known clean phase profile without spurs is different from the digital signal associated with the phase response.

13 . 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.

14 . The computer program product of claim 13 , wherein determining whether the sample waveform has spurs includes:
determining that the sample waveform has no spurs when the phase profile value of the phase response is inside the phase deviation tolerance.

15 . The computer program product of claim 13 , wherein the DAC and ADC pair in the target system are in a loopback connection.

16 . The computer program product of claim 15 , wherein the sample waveform is acquired from an output of the ADC.

17 . The computer program product of claim 13 , wherein the sample waveform is acquired from an output of the DAC.

18 . The computer program product of claim 13 , wherein a signal associated with the known clean phase profile without spurs is different from the digital signal associated with the phase response.

Assignees

• IBM

Inventors

• Lindquist Timothy
• Dahlen Paul E
• Zettles Iv George R
• Berge Layne A
• Haselhorst Kent H
• Ramirez Daniel

Classifications

• G10L21/14

  by displaying frequency domain information · CPC title

• G01R31/3167

  Testing of combined analog and digital circuits {(testing ADC's H03M1/1071)} · CPC title

• H04B1/1027

  assessing signal quality or detecting noise/interference for the received signal · CPC title

• G01R13/0272 Primary

  for sampling · CPC title

• G10L21/0232 Primary

  Processing in the frequency domain · CPC title