Method and apparatus for accommodating device and/or signal mismatch in a sensor array

Abstract

Noise discrimination in signals from a plurality of sensors is conducted by enhancing the phase difference in the signals such that off-axis pick-up is suppressed while on-axis pick-up is enhanced. Alternatively, attenuation/expansion are applied to the signals in a phase difference dependent manner, consistent with suppression of off-axis pick-up and on-axis enhancement. Nulls between sensitivity lobes are widened, effectively narrowing the sensitivity lobes and improving directionality and noise discrimination.

The invention claimed is: 
     
       1. A method for accommodating device and/or signal mismatch in a sensor array system having a plurality of sensors configured to generate a plurality of input signals including first and second sensors generating first and second input signals, the plurality of input signals being representable, at least one frequency, by input vectors each having a phase component and a magnitude component, including first and second input vectors, the method comprising:
 generating the first and second input signals from the first and second sensors;   processing, using a processor, the first and second input signals, the processing including, at the at least one frequency, using the magnitudes of the first and second input vectors to obtain corresponding first and second magnitude-matched vectors each having a magnitude that is substantially equal to one of an arithmetic mean, a geometric mean, a harmonic mean, or a root-mean-square of the magnitudes of two or more input vectors; and   generating an output signal having a magnitude that is a function of at least one of the first and second magnitude-matched vectors.   
     
     
       2. The method of  claim 1 , wherein the device and/or signal mismatch is accommodated at each of a plurality of frequencies. 
     
     
       3. The method of  claim 1 , further comprising enhancing an input phase difference of the first and second input vectors. 
     
     
       4. The method of  claim 3 , wherein enhancing comprises increasing or decreasing the input phase difference in a frequency-dependent manner using an expansion function. 
     
     
       5. The method of  claim 3 , wherein enhancing comprises increasing or decreasing the input phase difference in a frequency-dependent manner using a look-up table. 
     
     
       6. The method of  claim 3 , wherein enhancing is performed as a function of an adjustable sharpness parameter. 
     
     
       7. The method of  claim 6 , wherein the adjustable sharpness parameter is applied multiplicatively. 
     
     
       8. The method of  claim 6 , wherein the adjustable sharpness parameter is a function of frequency. 
     
     
       9. The method of  claim 6 , wherein the adjustable sharpness parameter is inversely proportional to frequency such that uniform sensitivity across the frequency spectrum is achieved. 
     
     
       10. The method of  claim 6 , wherein the adjustable sharpness parameter has one of multiple values, and its value depends on the sign of the phase difference between the first input vector and the second input vector. 
     
     
       11. The method of  claim 3 , wherein the enhancement of the input phase difference is computed using the ratio of the difference to the sum of the magnitudes of a pair of unit vectors corresponding to the first and second input vectors. 
     
     
       12. The method of  claim 1 , further comprising attenuating the magnitude-matched vectors by an attenuation factor that is a function of an input phase difference of the first and second input vectors. 
     
     
       13. The method of  claim 1 , further comprising combining the magnitude-matched vectors. 
     
     
       14. The method of  claim 13 , wherein combining comprises summing. 
     
     
       15. The method of  claim 13 , wherein combining comprises differencing. 
     
     
       16. The method of  claim 3 , wherein enhancing is conducted for phase difference values other than a selected phase difference value. 
     
     
       17. The method of  claim 3 , wherein zero enhancing is applied for a selected phase difference value, and enhancing greater than zero is applied for other phase difference values. 
     
     
       18. The method of  claim 12 , wherein attenuation is conducted for phase difference values other than a selected phase difference value. 
     
     
       19. The method of  claim 12 , wherein a maximum attenuation factor value is applied for a selected phase difference value, and attenuation factors of less than the maximum attenuation factor value are applied for other phase difference values. 
     
     
       20. The method of  claim 3 , wherein enhancing is conducted asymmetrically about a selected non-enhancement phase difference angle. 
     
     
       21. The method of  claim 12 , wherein attenuation is conducted asymmetrically about a selected non-attenuation phase angle difference. 
     
     
       22. A sensitivity matching circuit adapted to accommodate device and/or signal mismatch in a sensor array system having a plurality of sensors configured to generate a plurality of input signals including first and second sensors generating first and second input signals, the plurality of input signals being representable, at least one frequency, by input vectors each having a phase component and a magnitude component, including first and second input vectors, the sensitivity matching circuit comprising:
 one or more circuits adapted to generate the first and second input signals from the first and second sensors and process the first and second input signals, the processing including, at the at least one frequency, using the magnitudes of the first and second input vectors to obtain corresponding first and second magnitude-matched vectors each having a magnitude that is substantially equal to one of an arithmetic mean, a geometric mean, a harmonic mean, or a root-mean-square of the magnitude of two or more input vectors, the one or more circuits further adapted to generate an output signal having a magnitude that is a function of at least one of the first and second magnitude-matched vectors.   
     
     
       23. The method of  claim 22 , wherein the device and/or signal mismatch is accommodated at each of a plurality of frequencies. 
     
     
       24. The method of  claim 22 , further comprising enhancing an input phase difference of the first and second input vectors. 
     
     
       25. The method of  claim 24 , wherein enhancing comprises increasing or decreasing the input phase difference in a frequency-dependent manner using an expansion function. 
     
     
       26. The method of  claim 24 , wherein enhancing comprises increasing or decreasing the input phase difference in a frequency-dependent manner using a look-up table. 
     
     
       27. The method of  claim 24 , wherein enhancing is performed as a function of an adjustable sharpness parameter. 
     
     
       28. The method of  claim 27 , wherein the adjustable sharpness parameter is applied multiplicatively. 
     
     
       29. The method of  claim 27 , wherein the adjustable sharpness parameter is a function of frequency. 
     
     
       30. The method of  claim 27 , wherein the adjustable sharpness parameter is inversely proportional to frequency such that uniform sensitivity across the frequency spectrum is achieved. 
     
     
       31. The method of  claim 27 , wherein the adjustable sharpness parameter has one of multiple values, and its value depends on the sign of the phase difference between the first input vector and the second input vector. 
     
     
       32. The method of  claim 24 , wherein enhancing of the input phase difference is computed using the ratio of the difference to the sum of the magnitudes of a pair of unit vectors corresponding to the first and second input vectors. 
     
     
       33. The method of  claim 22 , further comprising attenuating the magnitude-matched vectors by an attenuation factor that is a function of an input phase difference of the first and second input vectors. 
     
     
       34. The method of  claim 22 , further comprising combining the magnitude-matched vectors. 
     
     
       35. The method of  claim 34 , wherein combining comprises summing. 
     
     
       36. The method of  claim 34 , wherein combining comprises differencing. 
     
     
       37. The method of  claim 24 , wherein enhancing is conducted for phase difference values other than a selected phase difference value. 
     
     
       38. The method of  claim 37 , wherein zero enhancing is applied for a selected phase difference value, and enhancing greater than zero is applied for other phase difference values. 
     
     
       39. The method of  claim 33 , wherein attenuation is conducted for phase difference values other than a selected phase difference value. 
     
     
       40. The method of  claim 33 , wherein a maximum attenuation factor value is applied for a selected phase difference value, and attenuation factors of less than the maximum attenuation factor value are applied for other phase difference values. 
     
     
       41. The method of  claim 24 , wherein enhancing is conducted asymmetrically about a selected non-enhancement phase difference angle. 
     
     
       42. The method of  claim 33 , wherein attenuation is conducted asymmetrically about a selected non-attenuation phase angle difference. 
     
     
       43. A method comprising:
 generating, by an input signal generator, first and second input signals from first and second sensors in a sensor array, wherein the first and second input signals are represented, at least at a frequency, by first and second input vectors each having a phase component and a magnitude component;   processing, using a processor, the first and second input signals, the processing including using the magnitude component of the first and second input vectors to obtain corresponding first and second output vectors each having a magnitude that is substantially equal to a mathematical mean of the magnitudes of two or more input vectors;   wherein the mathematical mean is a value selected from the group consisting of an arithmetic mean, a geometric mean, a harmonic mean, a root-mean-square, a logarithmic mean, and a particular mean selected based on characteristics of the first and second input signals; and   generating, by an output signal generator, an output signal, wherein the output signal is represented, at least at the frequency, by an output vector generated as a vector sum of the first and second output vectors.   
     
     
       44. The method of claim 43, wherein the mathematical mean is a value selected from the group consisting of an arithmetic mean, a geometric mean, a harmonic mean, and a root-mean-square.  
     
     
       45. The method of claim 43, wherein the processing and generating is performed at each of a plurality of frequencies.  
     
     
       46. The method of claim 43, further comprising enhancing an input phase difference of the first and second input vectors.  
     
     
       47. The method of claim 46, wherein the enhancing comprises increasing or decreasing the input phase difference in a frequency-dependent manner using an expansion function.  
     
     
       48. The method of claim 46, wherein the enhancing comprises increasing or decreasing the input phase difference in a frequency-dependent manner using a look-up table. 
     
     
       49. The method of claim 46, wherein the enhancing is performed as a function of an adjustable sharpness parameter. 
     
     
       50. The method of claim 49, wherein the adjustable sharpness parameter is applied multiplicatively. 
     
     
       51. The method of claim 49, wherein the adjustable sharpness parameter is a function of frequency. 
     
     
       52. The method of claim 49, wherein the adjustable sharpness parameter is inversely proportional to frequency such that uniform sensitivity across a frequency spectrum is achieved. 
     
     
       53. The method of claim 46, wherein enhancing is conducted asymmetrically about a selected non-enhancement phase difference angle.  
     
     
       54. The method of claim 46, wherein attenuation is conducted asymmetrically about a selected non-attenuation phase angle difference.  
     
     
       55. The method of claim 43, wherein the first input signal represents a signal originating from before the second input signal.  
     
     
       56. A sensitivity matching circuit comprising:
 one or more input signal generator circuits adapted to perform generating first and second input signals from a first and second sensor in a sensor array, wherein the first and second input signals are represented, at least at a frequency, by first and second input vectors each having a phase component and a magnitude component;   one or more processor circuits adapted to perform processing the first and second input signals, the processing including using the magnitude component of the first and second input vectors to obtain corresponding first and second output vectors each having a magnitude that is substantially equal to a mathematical mean of the magnitudes of two or more input vectors;   wherein the mathematical mean is a value selected from the group consisting of an arithmetic mean, a geometric mean, a harmonic mean, a root-mean-square, a logarithmic mean, and a particular mean selected based on characteristics of the first and second input signals; and   one or more output signal generator circuits adapted to perform generating an output signal, wherein the output signal is represented, at least at the frequency, by an output vector generated as a vector sum of the first and second output vectors.    
     
     
       57. The sensitivity matching circuit of claim 56, wherein the mathematical mean is a value selected from the group consisting of an arithmetic mean, a geometric mean, a harmonic mean, and a root-mean-square. 
     
     
       58. The sensitivity matching circuit of claim 56, wherein the processing and generating is performed at each of a plurality of frequencies. 
     
     
       59. The sensitivity matching circuit of claim 56, wherein the sensitivity matching circuit is further adapted to perform enhancing an input phase difference of the first and second input vectors.  
     
     
       60. The sensitivity matching circuit of claim 59, wherein the sensitivity matching circuit is further adapted to perform increasing or decreasing the input phase difference in a frequency-dependent manner using an expansion function.  
     
     
       61. The sensitivity matching circuit of claim 59, wherein the sensitivity matching circuit is further adapted to perform increasing or decreasing the input phase difference in a frequency-dependent manner using a look-up table.  
     
     
       62. The sensitivity matching circuit of claim 59, wherein the enhancing is performed as a function of an adjustable sharpness parameter.  
     
     
       63. The sensitivity matching circuit of claim 62, wherein the adjustable sharpness parameter is applied multiplicatively.  
     
     
       64. The sensitivity matching circuit of claim 62, wherein the adjustable sharpness parameter is a function of frequency.  
     
     
       65. The sensitivity matching circuit of claim 62, wherein the adjustable sharpness parameter is inversely proportional to frequency such that uniform sensitivity across a frequency spectrum is achieved.  
     
     
       66. The sensitivity matching circuit of claim 56, wherein the first input signal represents a signal originating from before the second input signal.  
     
     
       67. A system for signal processing, the system comprising:
 an input signal generator that generates first and second input signals from a first and second sensor in a sensor array, wherein the first and second input signals are represented, at least at a frequency, by first and second input vectors each having a phase component and a magnitude component;   a processor that processes the first and second input signals, the processing including using the magnitude component of the first and second input vectors to obtain corresponding first and second output vectors each having a magnitude that is substantially equal to a mathematical mean of the magnitudes of two or more input vectors;   wherein the mathematical mean is a value selected from the group consisting of an arithmetic mean, a geometric mean, a harmonic mean, a root-mean-square, a logarithmic mean, and a particular mean selected based on characteristics of the first and second input signals; and   an output signal generator that generates an output signal, wherein the output signal is represented, at least at the frequency, by an output vector generated as a vector sum of the first and second output vectors.    
     
     
       68. The system of claim 67, wherein the mathematical mean is a value selected from the group consisting of an arithmetic mean, a geometric mean, a harmonic mean, and a root-mean-square.  
     
     
       69. The system of claim 67, wherein the processing and generating is performed at each of a plurality of frequencies.  
     
     
       70. The system of claim 67, further comprising an enhancer that enhances an input phase difference of the first and second input vectors.  
     
     
       71. The system of claim 70, wherein the enhancer further performs increasing or decreasing the input phase difference in a frequency-dependent manner using an expansion function.  
     
     
       72. The system of claim 70, wherein the enhancer further performs increasing or decreasing the input phase difference in a frequency-dependent manner using a look-up table.  
     
     
       73. The system of claim 70, wherein the enhancing is performed as a function of an adjustable sharpness parameter.  
     
     
       74. The system of claim 73, wherein the adjustable sharpness parameter is applied multiplicatively.  
     
     
       75. The system of claim 73, wherein the adjustable sharpness parameter is a function of frequency.  
     
     
       76. The system of claim 73, wherein the adjustable sharpness parameter is inversely proportional to frequency such that uniform sensitivity across a frequency spectrum is achieved.  
     
     
       77. The system of claim 67, wherein the first input signal represents a signal originating from before the second input signal.