High and low voltage measurement in waveform analysis

• US 6,418,386 B1
• Filed: 12/06/1999
• Issued: 07/09/2002
• Est. Priority Date: 12/06/1999
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Naley, Mark Douglas, Wong-Lam, Ho Wai
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US09/455,127
• Time in Patent Office: 946 Days
• Field of Search: 702/57, 702/66, 702/67, 702/70, 702/71, 702/73, 702/180, 324/76.12, 324/76.13
• US Class Current: 702/66
• CPC Class Codes: G01R 13/34 Circuits for representing a single waveform by sampling, e.g. for very high frequencies

Abstract

The present invention is directed to systems and methods for analyzing high and low values in a period waveform in a manner that is applicable and accurate for both pulse-shaped waveforms and non-pulse-shaped waveforms. In an example implementation, a processor is adapted to generate a waveform histogram of the signal with weighted data samples, and to determine from the waveform histogram the high and low values in the waveform. Other aspects of the invention involve various manners in obtaining the weighted data samples.

Claims

1. A method for analyzing the waveform of a signal having high and low magnitudes, comprising:

generating a waveform histogram of the signal at least partially from weighted data samples of the signal; and

determining from the waveform histogram at least one of a high value and a low value in the waveform.

2. A method for analyzing the waveform of a signal, according to claim 1, wherein generating a waveform histogram includes weighting data corresponding to samples from the waveform.

3. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting by an amount that increases with the distance from a sampled-data region representing an immediately adjacent transition.

4. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting by an amount that decreases with the slope.

5. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting by an amount that increases with an increased magnitude of the sampled data relative to a waveform median value.

6. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting using a plurality of subweights, each subweight having a value that is defined as a function of a sampling count.

7. A method for analyzing the waveform of a signal, according to claim 6, wherein weighting using a plurality of subweights includes at least two of the following factors:

subweighting by an amount that increases with the distance from a sampled-data region representing an immediately adjacent high slope;

subweighting by an amount that decreases with the slope; and

subweighting by an amount that increases with an increased magnitude of the sampled data relative to a waveform median value.

8. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting sampled data with a weight W(n), where W(n) is a function of a plurality of subweights, W₁(n), W₂(n) and W₃(n), wherein n corresponds to a sample count and each of W₁(n), W₂(n) and W₃(n), respectively represents a different weighting amount.

9. A method for analyzing the waveform of a signal, according to claim 8, wherein:

subweight W₁(n) corresponds to an amount that increases with the distance from a sampled-data region representing an immediately adjacent high slope;

subweight W₂(n) corresponds to an amount that decreases with the slope; and

subweight W₃(n) corresponds to an amount that increases with an increased magnitude of the sampled data relative to a waveform median value.

10. A method for analyzing the waveform of a signal, according to claim 9, further including detecting transitions in the signal, and wherein subweight W₁(n) is reset to an initial value in response to detecting a transition in the signal.

11. A method for analyzing the waveform of a signal, according to claim 9, wherein subweight W₂(n) varies inversely proportionally with a normalized absolute slope magnitude at n.

12. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting sampled data with a weight W(n), where W(n)=W₁(n)×

W₂(n)×

W₃(n), wherein n corresponds to a sample count, W₁(n) corresponds to an amount that increases with the distance from a sampled-data region representing an immediately adjacent high slope;

W₂(n) corresponds to an amount that decreases with additional samples; and

W₃(n) corresponds to an amount that increases with an increased magnitude of the sampled data relative to a waveform median value.

13. A method for analyzing the waveform of a signal, according to claim 2, wherein weighting data includes weighting by a value that is a function of a sample count.

14. A method for analyzing the waveform of a signal, according to claim 1, wherein generating a waveform histogram includes generating a weighting function based on the waveform, the waveform being generated by applying the weighting function to data corresponding to samples from the waveform.

15. An apparatus for analyzing the waveform of a signal having high and low magnitudes, comprising:

generating means for generating a waveform histogram of the signal at least partially from weighted data samples of the signal; and

determining means for determining from the waveform histogram at least one of a high value and a low value in the waveform.

16. An apparatus, according to claim 15, wherein at least one of said generating means and said determining means is included as part of at least one of a test instrument, a programmable CPU, an oscilloscope, and a waveform simulator.

17. An apparatus, according to claim 15, wherein said generating means generate the waveform histogram of the signal by generating a weighting function based on the waveform and applying the weighting function to data corresponding to samples from the waveform.

18. An apparatus for analyzing the waveform of a signal having high and low magnitudes, comprising:

a signal receiver adapted to receive the waveform;

a processor arrangement adapted to generate a waveform histogram of the signal at least partially from weighted data samples of the signal, and to determine from the waveform histogram at least one of a high value and a low value in the waveform.

19. An apparatus, according to claim 18, wherein the processor arrangement is further adapted to determine from the waveform histogram high and low values in the waveform.

20. An apparatus, according to claim 18, wherein the processor arrangement is further adapted to weight data using a plurality of subweights, each subweight having a value that is defined as a function of a sampling count.

21. An apparatus, according to claim 18, wherein the processor arrangement is further adapted to weight using a plurality of subweights, the subweights including the following factors:

subweighting by an amount that increases with the distance from a sampled-data region representing an immediately adjacent high slope;

subweighting by an amount that decreases with the slope; and

subweighting by an amount that increases with an increased magnitude of the sampled data relative to a waveform median value.

22. An apparatus, according to claim 18, wherein the processor arrangement is further adapted to weight sampled data with a weight W(n), where W(n) is a function of a plurality of subweights, W₁(n), W₂(n) and W₃(n), wherein n corresponds to a sample count and each of W₁(n), W₂(n) and W₃(n), respectively represents a different weighting amount.

23. An apparatus, according to claim 22, wherein:

subweight W₁(n) corresponds to an amount that increases with the distance from a sampled-data region representing an immediately adjacent high slope;

subweight W₂(n) corresponds to an amount that decreases with additional samples; and

subweight W₃(n) corresponds to an amount that increases with an increased magnitude of the sampled data relative to a waveform median value.

24. An apparatus, according to claim 22, wherein subweight W₁(n) is reset to an initial value in response to detecting a transition in the signal.

25. An apparatus, according to claim 18, wherein the processor arrangement generates the waveform histogram of the signal by generating a weighting function based on the waveform and applying the weighting function to data corresponding to samples from the waveform.