Frequency rectification tool for shorter waveforms

• US 7,064,556 B2
• Filed: 05/04/2004
• Issued: 06/20/2006
• Est. Priority Date: 05/04/2004
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Grant, John W., Malakhova, Olga, Petchenev, Alexei, Littrell, Nathan B.
• Primary Examiner(s): Benson, Walter
• Application Number:
  US10/838,459
• Publication Number:
  US 20050248354A1
• Time in Patent Office: 777 Days
• Field of Search: 324/76.11, 324/76.12, 324/76.19, 324/76.27, 324/76.28, 324/613, 331/78, 375/334
• US Class Current: 324/613
• CPC Class Codes: G01R 19/0053 Noise discrimination; Analog sampling; Measuring transients measuring characteristics of individual pulses G01R29/02; digital sampling G01R19/2509; measuring noise figure G01R29/26
• CPC Class Codes: G01R 31/343 in operation

Abstract

A method of detecting a signal (S) of interest contained within a waveform (F) comprised of a plurality of signals within a frequency spectrum, as well as random noise. After first detecting the waveform, a determination is made as to whether the duration (Td) of the waveform is sufficient for subsequent processing. If the duration is not sufficient, the waveform is concatenated with itself to produce a waveform of sufficient duration. The concatenated waveform is then processed and the results supplied as an input to an oscillator (24) operating at a nominal output frequency. The oscillator cancels the effects of noise in the waveform and the frequency of the oscillator shifts to a different frequency which is a function of the signal of interest. The shift in output frequency of the oscillator is detected and analyzed to obtain the signal of interest. The oscillator can be either a general purpose oscillator or a Van der Pol oscillator.

Claims

1. A method of detecting a signal (S) of interest contained within a waveform (F) comprised of a plurality of frequencies within a frequency spectrum, as well as random noise, comprising:

capturing the waveform starting at any instant of time;

converting the waveform from analog to digital;

processing the digitized waveform; and

,

supplying results of the processing as an input to an oscillator (24) using dynamic synchronization, the oscillator operating at a nominal output frequency which is near that of the signal of interest, the oscillator canceling the effects of the noise in the waveform and shifting its output frequency to a different frequency which is a function of the signal of interest.

2. The method of claim 1 further including detecting the output frequency of the oscillator and analyzing the shift in frequency to detect the signal of interest.

3. The method of claim 1 further including determining if the duration (Td) of the waveform is sufficient for the oscillator to respond to the input to shift its output frequency to that of the signal of interest.

4. The method of claim 3 further including concatenating the waveform with itself a sufficient number of times to produce a waveform of sufficient duration.

5. The method of claim 3 wherein capturing the waveform includes applying the waveform to a universal relay (12).

6. The method of claim 5 further including converting an output from the universal relay from an analog to a digital waveform.

7. The method of claim 6 in which the digitized waveform is concatenated to produce of waveform of sufficient duration for use with the oscillator.

8. The method of claim 1 in which the oscillator is a general purpose oscillator.

9. The method of claim in 1 which the oscillator is a Van der Pol oscillator.

10. Apparatus for detecting a signal (S) of interest contained within a waveform (F) comprised of a plurality of frequencies within a frequency spectrum, as well as random noise, comprising:

means (12) for capturing the waveform starting at any instant of time;

means (20) converting the waveform from analog to digital;

means (22) processing the digitized waveform; and

,

means for supplying results of the processing as an input to an oscillator (24) using dynamic synchronization, the oscillator (24) operating at a nominal output frequency which is near that of the signal of interest to which the processed digitized waveform is supplied as an input, the oscillator canceling the effects of the noise in the waveform and shifting its output frequency to a different frequency which is a function of the signal of interest.

13. The apparatus of claim 10 further including means (26, 28) detecting the output frequency of the oscillator and analyzing the shift in frequency to detect the signal of interest.

14. The apparatus of claim 10 further including concatenating means (21) determining if the duration (Td) of the waveform is sufficient for the oscillator to respond to the input to shift its output frequency to that of the signal of interest.

15. The apparatus of claim 14 wherein, if the duration of the waveform is insufficient, the concatenating means appends the waveform with itself a sufficient number of times to produce a waveform of that is of a sufficient duration.

16. The apparatus of claim 10 wherein the means (12) for capturing the waveform includes a universal relay.

11. The apparatus 10 in which the oscillator is a general purpose oscillator.

12. The apparatus 10 in which the oscillator is a Van der Pol oscillator.

17. A method of detecting a signal (S) of interest contained within a waveform (F) comprised of a plurality of frequencies within a frequency spectrum, as well as random noise, comprising:

detecting the waveform starting at any instant of time;

determining if the duration (Td) of the waveform is of a sufficient duration for subsequent processing;

if the duration of the waveform is of insufficient duration, concatenating the waveform with itself to produce a waveform of sufficient duration; and

,

processing the concatenated waveform and supplying results of the processing as an input to an oscillator (24) using dynamic synchronization, the oscillator operating at a nominal output frequency which is near that of the signal of interest, the oscillator canceling the effects of the noise in the waveform and shifting its output frequency to a different frequency which is a function of the signal of interest.

18. The method of claim 17 in which the oscillator is a general purpose oscillator.

19. The method of claim 17 in which the oscillator is a Van der Pol oscillator.

20. The method of claim 17 further including detecting the output frequency of the oscillator and analyzing the shift in frequency to detect the signal of interest.

21. The method of claim 20 further including operating the oscillator at a frequency near that of the signal of interest.

22. The method of claim 21 wherein capturing the waveform includes applying the waveform to a universal relay (12).