Method and apparatus for acquiring wide-band pseudorandom noise encoded waveforms

• US 6,380,879 B2
• Filed: 12/04/2000
• Issued: 04/30/2002
• Est. Priority Date: 08/21/1997
• Status: Expired due to Term

• Current Assignee: Data Fusion Corp.
• Original Assignee: Data Fusion Corp.
• Inventors: Thomas, John K., Kober, Wolfgang
• Primary Examiner(s): WAMSLEY, PATRICK G
• Application Number:
  US09/730,316
• Publication Number:
  US 20010000660A1
• Time in Patent Office: 512 Days
• Field of Search: 341/155, 341/126, 370/288, 375/240, 379/420, 704/230, 704/208, 704/229, 704/203, 704/200, 348/389, 348/434, 348/436
• US Class Current: 341/155
• CPC Class Codes: G01S 1/045 Receivers
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: H03M 1/121 Interleaved, i.e. using multiple converters or converter parts for one channel

Abstract

The method and apparatus of the present invention is directed to architectures for signal processing, such as for performing analog-to-digital and digital-to-analog conversions, in which the source signal is decomposed into subband signals by an analysis filter, processed, and the processed subband signals combined to form a reconstructed signal that is representative of the source signal.

Claims

1. A method for acquiring a signal having a bandwidth, comprising:

decomposing the signal into a plurality of signal segments, each signal segment having a signal segment bandwidth that is less than the signal bandwidth;

processing each of the signal segments to form a plurality of processed signal segments; and

combining the processed signal segments into a composite signal, wherein the signal is in one of analog or digital form and the composite signal is in the other one of analog or digital form, and wherein the processing step includes removing a noise component from each of the signal segments to form a corresponding plurality of noise reduced signal segments and thereafter converting each of the noise reduced signal segments from one of analog or digital form to the other one of analog or digital form.

2. The method of claim 1, wherein the processing step comprises:

assigning boundary values to a plurality of bins;

sampling a signal segment to provide a sampled value corresponding to the sampled portion of the signal segment;

comparing the sampled value with assigned boundary values for each of the plurality of bins;

selecting an appropriate bin for the sampled portion of the signal segment;

thereafter reassigning new boundary values to at least a portion of the plurality of bins; and

repeating the assigning, sampling, comparing and selecting steps.

3. The method of claim 2, wherein each bin corresponds to a number of bits, wherein a first number of bits is assigned to a first bin and a second number of bits is assigned to a second bin, the first number being more than the second number, and wherein the first bin corresponds to a first portion of a signal segment and the second bin corresponds to a second portion of a signal segment, the first portion of the signal segment having less noise than the second portion of the signal segment.

4. The method of claim 1, wherein the processing step includes performing analog-to-digital conversion of each of the signal segments.

5. The method of claim 1, wherein the processing step includes performing digital-to-analog conversion of each of the signal segments.

6. The method of claim 1, wherein in the processing step each of the signal segments is processed separately.

7. The method of claim 1, wherein the composite signal has the same bandwidth as the signal bandwidth.

8. The method of claim 1, wherein the composite signal is a time delayed replica of the signal.

9. The method of claim 1, wherein the signal has a bandwidth of at least about 1 GHz.

10. The method of claim 1, wherein the sum of the plurality of signal bandwidths is equivalent to the signal bandwidth.

11. The method of claim 1, wherein the signal is in analog form and the composite signal is in digital form.

12. The method of claim 1, wherein the acquired signal is analog and wherein the decomposing step is performed by at least one of a plurality of low pass filters, a plurality of high pass filters, a combination of band reject and low pass filters, a combination of band reject and high pass filters, and a plurality of band reject filters.

13. The method of claim 1, wherein the noise components are removed by at least one of a noise reducing quantizer, a noise filter, and a rank reducer.

14. The method of claim 1, wherein each of the signal segment bandwidths overlaps an adjacent signal segment bandwidth by no more than about 5%.

15. A method for reducing noise in a signal having a bandwidth, comprising:

decomposing the signal into at least a plurality of signal segments, each signal segment having a bandwidth that is less than the bandwidth of the signal and

removing a noise component from each of the signal segments to form a corresponding plurality of processed signal segments.

16. The method of claim 15, further comprising:

combining each of the processed signal segments to form a composite signal.

17. The method of claim 16, further comprising:

combining the plurality of processed signal segments to form a composite signal.

18. The method of claim 17, wherein the composite signal has the same bandwidth as the signal.

19. The method of claim 15, wherein the removing step comprises:

assigning boundary values to a plurality of bins;

sampling a signal segment to provide a sampled value corresponding to the sampled portion of the signal segment;

comparing the sampled value with assigned boundary values for each of the plurality of bins;

selecting an appropriate bin for the sampled portion of the signal segment;

thereafter reassigning new boundary values to at least a portion of the plurality of bins; and

repeating the assigning, sampling, comparing and selecting steps.

20. The method of claim 19, wherein each bin corresponds to a number of bits, wherein a first number of bits is assigned to a first bin and a second number of bits is assigned to a second bin, the first number being more than the second number, and wherein the first bin corresponds to a first portion of a signal segment and the second bin corresponds to a second portion of a signal segment, the first portion of the signal segment has less noise than the second portion of the signal segment.

21. The method of claim 15, wherein the signal is analog and wherein the decomposing step is performed by at least one of a plurality of low pass filters, a plurality of high pass filters, a combination of band reject and low pass filters, a combination of band reject and high pass filters, and a plurality of band reject filters.

22. The method of claim 15, wherein the noise component is removed by at least one of a noise reducing quantizer, a noise filter, and a rank reducer.

23. The method of claim 15, wherein each of the signal segment bandwidths overlaps an adjacent signal segment bandwidth by no more than about 5%.

24. A system for reducing noise in a signal having a bandwidth, comprising:

means for decomposing the signal into at least a plurality of signal segments, each signal segment having a bandwidth that is less than the bandwidth of the signal and

means for removing a noise component from each of the signal segments to form a corresponding plurality of processed signal segments.

25. The system of claim 24, further comprising:

means for combining each of the processed signal segments to form a composite signal.

26. The system of claim 25, wherein the composite signal has the same bandwidth as the signal.

27. The system of claim 25, wherein the signal is digital.

28. The system of claim 24, further comprising:

means for assigning boundary values to a plurality of bins;

means for sampling a signal segment to provide a sampled value corresponding to the sampled portion of the signal segment;

means for comparing the sampled value with assigned boundary values for each of the plurality of bins;

means for selecting an appropriate bin for the sampled portion of the signal segment; and

means for thereafter reassigning new boundary values to at least a portion of the plurality of bins.

29. The method of claim 28, wherein each bin corresponds to a number of bits, wherein a first number of bits is assigned to a first bin and a second number of bits is assigned to a second bin, the first number being more than the second number, and wherein the first bin corresponds to a first portion of a signal segment and the second bin corresponds to a second portion of a signal segment, the first portion of the signal segment has less noise than the second portion of the signal segment.

30. The system of claim 24, wherein the signal is analog and wherein the decomposing means is at least one of a plurality of low pass filters, a plurality of high pass filters, a combination of band reject and low pass filters, a combination of band reject and high pass filters, and a plurality of band reject filters.

31. The system of claim 24, wherein the removing means is at least one of a noise reducing quantizer, a noise filter, and a rank reducer.

32. The system of claim 24, wherein each of the signal segment bandwidths overlaps an adjacent signal segment bandwidth by no more than about 5%.

33. A method for reducing noise in a first signal having a first bandwidth, comprising:

decomposing the first signal into a plurality of subband signals, each subband signal having a bandwidth that is less than the first bandwidth;

rejecting a noise component of at least one of the subband signals; and

thereafter combining at least a portion of the subband signals to form a second signal.

34. The method of claim 33, wherein the rejecting step comprises:

assigning boundary values to a plurality of bins;

sampling a subband signal to provide a sampled value corresponding to the sampled portion of the subband signal;

comparing the sampled value with assigned boundary values for each of the plurality of bins;

selecting an appropriate bin for the sampled portion of the subband signal;

thereafter reassigning new boundary values to at least a portion of the plurality of bins; and

repeating the assigning, sampling, comparing and selecting steps.

35. The method of claim 34, wherein each bin corresponds to a number of bits, wherein a first number of bits is assigned to a first bin and a second number of bits is assigned to a second bin, the first number being more than the second number, and wherein the first bin corresponds to a first portion of a subband signal and the second bin corresponds to a second portion of the subband signal, the first portion of the subband signal having less noise than the second portion of the subband signal.

36. The method of claim 33, wherein the second signal has the a second bandwidth and the first and second bandwidths are at least substantially the same.

37. The method of claim 33, wherein the first signal is analog and wherein the decomposing step is performed by at least one of a plurality of low pass filters, a plurality of high pass filters, a combination of band reject and low pass filters, a combination of band reject and high pass filters, and a plurality of band reject filters.

38. The method of claim 33, wherein the noise component is rejected by at least one of a noise reducing quantizer, a noise filter, and a rank reducer.

39. The method of claim 33, wherein each of the subband signal bandwidths overlaps an adjacent subband signal bandwidth by no more than about 5%.

40. The method of claim 33, wherein the rejecting step comprises:

determining whether the noise component of the at least one of the subband signals equals or exceeds a predetermined level; and

when the noise component equals or exceeds the predetermined level, discarding the respective at least one of the subband signals, wherein the respective at least one of the subband signals is not part of the second signal.

41. The method of claim 33, wherein the rejecting step comprises:

removing the noise component from the respective at least one of the subband signals and wherein the noise reduced respective at least one of the subband signals is part of the second signal.

42. A system for reducing noise in a first signal having a first bandwidth, comprising:

means for decomposing the first signal into a plurality of subband signals, each subband signal having a bandwidth that is less than the first bandwidth;

means for rejecting a noise component of at least one of the subband signals; and

means for combining each of the subband signals to form a second signal.

43. The system of claim 42, wherein the first signal is analog and wherein the decomposing means is performed by at least one of a plurality of low pass filters, a plurality of high pass filters, a combination of band reject and low pass filters, a combination of band reject and high pass filters, and a plurality of band reject filters.

44. The system of claim 42, wherein the rejecting means is at least one of a noise reducing quantizer, a noise filter, and a rank reducer.

45. The system of claim 42, wherein each of the subband signal bandwidths overlaps an adjacent subband signal bandwidth by no more than about 5%.

46. The system of claim 42, wherein the second signal has a second bandwidth and the first and second bandwidths are at least substantially the same.

47. A system for reducing noise in a first signal having a first bandwidth, comprising:

a decomposition filter bank that decomposes the first signal into a plurality of subband signals, each subband signal having a bandwidth that is less than the first bandwidth; and

a noise rejecter that rejects at least a portion of a noise component in at least a portion of the subband signals.

48. The system of claim 47, further comprising:

a reconstruction filter bank that combines at least a portion of the subband signals to form a second signal.

49. The system of claim 48, wherein the second signal has a second bandwidth and the first and second bandwidths are at least substantially the same.

50. The system of claim 47, further comprising:

an assigner that assigns boundary values to a plurality of bins;

a quantizer that samples a subband signal to provide a sampled value corresponding to the sampled portion of the subband signal;

a comparer that compares the sampled value with assigned boundary values for each of the plurality of bins;

a selecter that selects an appropriate bin for the sampled portion of the subband signal; and

a reassigner that thereafter reassigns new boundary values to at least a portion of the plurality of bins.

51. The method of claim 50, wherein each bin corresponds to a number of bits, wherein a first number of bits is assigned to a first bin and a second number of bits is assigned to a second bin, the first number being more than the second number, and wherein the first bin corresponds to a first portion of a subband signal and the second bin corresponds to a second portion of the subband signal, the first portion of the subband signal having less noise than the second portion of the subband signal.

52. The system of claim 47, wherein the first signal is analog and wherein the decomposition filter bank is at least one of a plurality of low pass filters, a plurality of high pass filters, a combination of band reject and low pass filters, a combination of band reject and high pass filters, and a plurality of band reject filters.

53. The system of claim 47, wherein the noise rejecter is at least one of a noise reducing quantizer, a noise filter, and a rank reducer.

54. The system of claim 47, wherein each of the subband signal bandwidths overlaps an adjacent subband signal bandwidth by no more than about 5%.

55. The method of claim 47, wherein the noise rejecter comprises:

a comparer that determines whether the noise component of the at least one of the subband signals equals or exceeds a predetermined level; and

when the noise component equals or exceeds the predetermined level, a signal discarder that discards the respective at least one of the subband signals, wherein the respective at least one of the subband signals is not part of the second signal.

56. The method of claim 47, wherein the noise rejecter removes the noise component from the respective at least a portion of the subband signals and wherein the noise reduced respective at least a portion of the subband signals is part of the second signal.