Waveform signal analyzer

• US 6,542,836 B1
• Filed: 03/23/2000
• Issued: 04/01/2003
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sawada, Akira, Sasaki, Keiichi
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Kim, Paul L
• Application Number:
  US09/533,937
• Time in Patent Office: 1,104 Days
• Field of Search: 702/66, 702/70, 702/73, 702/77, 375/240.19, 375/240.18, 375/239
• US Class Current: 702/66
• CPC Class Codes: G01R 23/16 Spectrum analysis; Fourier analysis

Abstract

The waveform signal analyzer of the present invention is equipped with:

input means 10 that inputs a waveform signals;

period detection means 20 that detects the period of the waveform signals inputted by input means 10; and

division means 30 that divides the waveform signals by the period detected by period detection means 20.

Wavelet transformation means 40 performs wavelet transformation of each individual division of the waveform signals. Display means 50 consecutively displays in time series the wavelet transformation results of each individual division of the waveform signals.

Claims

1. A waveform signal analyzer, comprising:

an input means for inputting waveform signals;

a period detection means for detecting a periodicity of said waveform signals inputted by said input means;

a division means for dividing said waveform signals based on said periodicity detected by said period detection means;

a wavelet transformation means for wavelet-transforming each individual division of said waveform signals; and

a display means for consecutively displaying in time series said wavelet transformation results of each individual division of said waveform signals.

2. A waveform signal analyzer according to claim 1, wherein:

said wavelet transformation means has

a mother wavelet selection unit that designates a type of mother wavelet;

a transformation range designation unit that designates a time domain that is taken as a target for wavelet transformation;

a transformation parameter setting unit that sets scale parameters and shift parameters for wavelet transformation;

a wavelet computing unit that calculates wavelet coefficients; and

an output unit that outputs wavelet transformation results.

3. A waveform signal analyzer according to claim 1 or claim 2, wherein:

said period detection means has

a Fourier transformation unit that performs Fourier transformation on said waveform signals inputted by said input means and obtains a Fourier spectrum; and

a period identification unit that identifies said period of said waveform signals from said Fourier spectrum obtained by said Fourier transformation unit.

4. A waveform signal analyzer according to claim 1, wherein said division means comprises:

a period setting unit that sets a division period by using one of (1) an integer multiplication of said period detected by said period detection means and (2) a period of a pilot signal that is pre-synchronized with said inputted waveform signals; and

means for setting a division position using said pilot signal, when the division period is set using the period of the pilot signal.

5. A waveform signal analyzer according to claim 1, wherein said display means further comprises:

means for outputting wavelet transformation results using different colors for each numerical range of wavelet strength.

6. A waveform signal analyzer according to claim 1, wherein said display means further comprises:

means for combining a plurality of wavelet transformation results according to designated frequency domains.

7. A waveform signal analyzer according to claim 1, wherein said display means comprises:

a marker operating unit for designating desired portions on a display screen, and, when a wavelet transformation result is designated on said display screen by said marker operating unit, said display means displays time, frequency, and strength of said wavelet transformation result on said display screen.

8. A waveform signal analyzer according to claim 1, wherein said display means further comprises:

a computing unit that computes (1) differences and variation rates of different wavelet transformation results and (2) a mean of all said transformation results.

9. A waveform signal analyzer according to claim 1, wherein said display means further comprises:

means for displaying one of (1) said time variation of peak strengths in a designated frequency, which is a cross-section of said wavelet transformation results on a frequency axis and (2) a peak strength distribution of each frequency component at a designated moment in time, which is a cross-section on a time axis.

10. A waveform signal analyzer according to claim 2, wherein said division means comprises:

a period setting unit that sets a division period by using one of (I) an integer multiplication of said period detected by said period detection means and (2) a period of a pilot signal that is pre-synchronized with said inputted waveform signals; and

means for setting a division position using said pilot signal, when the division period is set using the period of the pilot signal.

11. A waveform signal analyzer according to claim 2, wherein said display means further comprises:

means for outputting wavelet transformation results using different colors for each numerical range of wavelet strength.

12. A waveform signal analyzer according to claim 2, wherein said display means further comprises:

means for combining a plurality of wavelet transformation results according to designated frequency domains.

13. A waveform signal analyzer according to claim 2, wherein said display means comprises:

a marker operating unit for designating desired portions on a display screen, and, when a wavelet transformation result is designated on said display screen by said marker operating unit, said display means displays time, frequency, and strength of said wavelet transformation result on said display screen.

14. A waveform signal analyzer according to claim 2, wherein said display means further comprises:

a computing unit that computes (1) differences and variation rates of different wavelet transformation results and (2) a mean of all said transformation results.

15. A waveform signal analyzer according to claim 2, wherein said display means further comprises:

means for displaying one of (1) said time variation of peak strengths in a designated frequency, which is a cross-section of said wavelet transformation results on a frequency axis and (2) a peak strength distribution of each frequency component at a designated moment in time, which is a cross-section on a time axis.

18. A waveform signal analyzer according to claim 8, wherein:

said period detection means has a function of being designed to detect a maximum value and a minimum value within a designated time-frequency domain, a centroid and a designated domain start time or a designated domain end time in said wavelet-transformation results.

16. A waveform signal analyzer, comprising:

an input means for inputting waveform signals;

a wavelet transformation means for performing wavelet transformation of waveform signals inputted by said input means;

a period detection means for detecting a periodicity of results of transformation by said wavelet transformation means;

a division means for dividing said transformation results, based on said periodicity detected by said period detection means; and

a display means for consecutively displaying said divided transformation results in time series.

17. A waveform signal analyzer according to claim 16, wherein:

said period detection means has

a Fourier transformation unit that performs Fourier transformation of said wavelet transformation results and obtains a Fourier spectrum; and

a period identification unit that identifies said period of said transformation results from said Fourier spectrum obtained by said Fourier transformation unit.