CA2524162A1 - Periodic signal enhancement system - Google Patents
Periodic signal enhancement system Download PDFInfo
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- CA2524162A1 CA2524162A1 CA002524162A CA2524162A CA2524162A1 CA 2524162 A1 CA2524162 A1 CA 2524162A1 CA 002524162 A CA002524162 A CA 002524162A CA 2524162 A CA2524162 A CA 2524162A CA 2524162 A1 CA2524162 A1 CA 2524162A1
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- signal
- filter
- enhancement system
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- 230000000737 periodic effect Effects 0.000 title 1
- 230000003044 adaptive effect Effects 0.000 claims abstract 40
- 230000003111 delayed effect Effects 0.000 claims abstract 12
- 230000002787 reinforcement Effects 0.000 claims abstract 9
- 238000000034 method Methods 0.000 claims 18
- 230000006978 adaptation Effects 0.000 claims 8
- 238000001914 filtration Methods 0.000 claims 8
- 230000001934 delay Effects 0.000 claims 4
- 230000003014 reinforcing effect Effects 0.000 claims 3
- 230000002708 enhancing effect Effects 0.000 claims 2
- 230000007423 decrease Effects 0.000 claims 1
- 230000003247 decreasing effect Effects 0.000 claims 1
- 230000005236 sound signal Effects 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0316—Speech enhancement, e.g. noise reduction or echo cancellation by changing the amplitude
- G10L21/0364—Speech enhancement, e.g. noise reduction or echo cancellation by changing the amplitude for improving intelligibility
Landscapes
- Engineering & Computer Science (AREA)
- Computational Linguistics (AREA)
- Quality & Reliability (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Filters That Use Time-Delay Elements (AREA)
Abstract
A signal enhancement system improves the understandability of speech or othe r audio signals. The system reinforces selected parts of the signal, may attenuate selected parts of the signal, and may increase SNR. The system includes delay logic, a partitioned adaptive filter, and signal reinforcement logic. The partitioned adaptive filter may track and enhance the fundamental frequency and harmonics in the input signal. The partitioned filter output signals may approximately reproduce the input signal, delayed by an integer multiple of the period of the fundamental frequency of the inp ut signal. The reinforcement logic combines the input signal and the filtered signals t o produce an enhanced output signal.
Claims (67)
1. A signal enhancement system comprising:
a signal input;
partitioned delay logic coupled to the signal input;
a partitioned adaptive filter coupled to the partitioned delay logic and comprising multiple adaptive filter outputs;
filter reinforcement logic coupled to the adaptive filter outputs;
gain logic coupled to the filter reinforcement logic; and signal reinforcement logic coupled to the signal input and the gain logic and comprising an enhanced signal output.
a signal input;
partitioned delay logic coupled to the signal input;
a partitioned adaptive filter coupled to the partitioned delay logic and comprising multiple adaptive filter outputs;
filter reinforcement logic coupled to the adaptive filter outputs;
gain logic coupled to the filter reinforcement logic; and signal reinforcement logic coupled to the signal input and the gain logic and comprising an enhanced signal output.
2. The signal enhancement system of claim 1, where the multiple filter outputs comprise a first filter output and a second filter output, and where the partitioned adaptive filter comprises:
a first adaptive filter comprising:
first filter coefficients;
the first filter output; and a first error output;
a second adaptive filter comprising:
second filter coefficients;
the second filter output; and a second error output, wherein the first filter coefficients are adapted based on the first error output and the second filter coefficients are adapted based on the second error output.
a first adaptive filter comprising:
first filter coefficients;
the first filter output; and a first error output;
a second adaptive filter comprising:
second filter coefficients;
the second filter output; and a second error output, wherein the first filter coefficients are adapted based on the first error output and the second filter coefficients are adapted based on the second error output.
3. The signal enhancement system of claim 2, where the first error output comprises a first difference between the signal input and the first filter output, and where the second error output comprises a second difference between the signal input and the second filter output.
4. The signal enhancement system of claim 2, where delay logic comprises an M1 sample delay coupled to the first adaptive filter and an M2 sample delay coupled to the second adaptive filter.
5. The signal enhancement system of claim 4, where the M2 sample delay is in series with the M1 sample delay.
6. The signal enhancement system of claim 4, where the first adaptive filter is a length M1 adaptive filter and where the second adaptive filter is a length M2 adaptive filter.
7. The signal enhancement system of claim 6, where M1=M2.
8. The signal enhancement system of claim 6, where M1=M2=1.
9. The signal enhancement system of claim 4, where the first filter has a length smaller than M1 or the second filter has a length smaller than M2.
10. The signal enhancement system of claim 4, where the first filter has a length greater than M1 or the second filter has a length greater than M2.
11. The signal enhancement system of claim 1, where the delay logic comprises a D
sample delay selected to set a maximum adaptation pitch.
sample delay selected to set a maximum adaptation pitch.
12. The signal enhancement system of claim 1, where the delay logic comprises an L sample delay selected to set an adaptation pitch range.
13. The signal enhancement system of claim 1, where the delay logic implements an adaptation pitch range including a human voice pitch.
14. The system of claim 1, where the delay logic implements an adaptation pitch range between approximately 70 Hz and approximately 400 Hz.
15. ~The system of claim 1, further comprising a first stage filter comprising quasi-stationary frequency tracking and attenuation logic, where the first stage filter is coupled between the signal input and to the delay logic.
16. ~A signal enhancement system comprising:
means for receiving an input signal;
means for delaying the input signal by multiple different delays;
means for partitioned adaptive filtering the input signal based on the multiple different delays; and means for reinforcing the input signal with a partitioned adaptive filtering output.
means for receiving an input signal;
means for delaying the input signal by multiple different delays;
means for partitioned adaptive filtering the input signal based on the multiple different delays; and means for reinforcing the input signal with a partitioned adaptive filtering output.
17. ~The signal enhancement system of claim 16, further comprising:
means for biasing the partitioned adaptive filtering output.
means for biasing the partitioned adaptive filtering output.
18. ~The signal enhancement system of claim 16, further comprising:
means for tracking and filtering a quasi-stationary signal in the input signal prior to filtering the input signal.
means for tracking and filtering a quasi-stationary signal in the input signal prior to filtering the input signal.
19. ~The signal enhancement system of claim 16, further comprising means for adapting the means for partitioned adaptive filtering based on multiple error signals.
20. ~A signal enhancement system comprising:
a signal input;
an M1 sample delay coupled to the signal input;
an M2 sample delay coupled to the M1 sample delay;
a first adaptive filter coupled to the M1 sample delay and comprising a first filter output;
a second adaptive filter coupled to the M2 sample delay and comprising a second filter output;
filter reinforcement logic connected to the first filter output and the second filter output; and signal reinforcement logic connected to the signal input and the filter reinforcement logic.
a signal input;
an M1 sample delay coupled to the signal input;
an M2 sample delay coupled to the M1 sample delay;
a first adaptive filter coupled to the M1 sample delay and comprising a first filter output;
a second adaptive filter coupled to the M2 sample delay and comprising a second filter output;
filter reinforcement logic connected to the first filter output and the second filter output; and signal reinforcement logic connected to the signal input and the filter reinforcement logic.
21. ~The signal enhancement system of claim 20, where the first adaptive filter comprises a first error output based on the input signal and the first filter output, and where the first adaptive filter comprises first coefficients adapted based on the first error output.
22. ~The signal enhancement system of claim 21, where the second adaptive filter comprises a second error output based on the input signal and the second filter output, and where the second adaptive filter comprises second coefficients adapted based on the second error output.
23. ~The signal enhancement system of claim 20, where M1=M2.
24. ~The signal enhancement system of claim 20, where M1=M2=1.
25. ~The signal enhancement system of claim 20, further comprising an initial D
sample delay coupled to the M1 sample delay, where 'D' is chosen to set a maximum adaptation pitch.
sample delay coupled to the M1 sample delay, where 'D' is chosen to set a maximum adaptation pitch.
26. ~The signal enhancement system of claim 25 where the D sample delay, the sample delay, and the M2 sample delay implement an adaptation pitch range including that of human voice.
27. ~The signal enhancement system of claim 25 where the D sample delay, the sample delay, and the M2 sample delay implement an adaptation pitch range between approximately 70 Hz and approximately 400 Hz.
28. ~The signal enhancement system of claim 20, further comprising a gain logic coupled to the filter reinforcement logic.
29. The signal enhancement system of claim 20, further comprising a slowly adapting first stage filter coupled to the signal input.
30. The signal enhancement system of claim 29, where the first stage filter comprises quasi-stationary signal tracking and attenuation logic.
31. A method for enhancing a signal, comprising:
receiving an input signal comprising a fundamental frequency;
delaying the input signal by multiple different sample delays to obtain multiple differently delayed input signals;
applying a partitioned adaptive filter comprising multiple individual adaptive filters to the multiple differently delayed input signals;
generating a filtered output with the partitioned adaptive filter, the filtered output approximately delayed by an integer multiple of the fundamental frequency;
generating an error signal for each of the multiple individual adaptive filters;
adapting each of the individual adaptive filters based on the error signal for that individual adaptive filter; and reinforcing the input signal with the filtered output.
receiving an input signal comprising a fundamental frequency;
delaying the input signal by multiple different sample delays to obtain multiple differently delayed input signals;
applying a partitioned adaptive filter comprising multiple individual adaptive filters to the multiple differently delayed input signals;
generating a filtered output with the partitioned adaptive filter, the filtered output approximately delayed by an integer multiple of the fundamental frequency;
generating an error signal for each of the multiple individual adaptive filters;
adapting each of the individual adaptive filters based on the error signal for that individual adaptive filter; and reinforcing the input signal with the filtered output.
32. The method of claim 31, further comprising:
forming a sum of outputs of the multiple adaptive filters;
biasing the sum by a gain parameter.
forming a sum of outputs of the multiple adaptive filters;
biasing the sum by a gain parameter.
33. The method of claim 31, further comprising:
determining a maximum pitch to track;
and where delaying the input signal comprises delaying the input signal by D
samples, where D is selected according to the maximum pitch.
determining a maximum pitch to track;
and where delaying the input signal comprises delaying the input signal by D
samples, where D is selected according to the maximum pitch.
34. The method of claim 33, further comprising:
selecting a pitch tracking range;
and where delaying the input signal comprises delaying the input signal by D +
L samples, where L is selected to set the pitch tracking range.
selecting a pitch tracking range;
and where delaying the input signal comprises delaying the input signal by D +
L samples, where L is selected to set the pitch tracking range.
35. ~The method of claim 34, where the pitch range includes a human voice pitch.
36. ~The method of claim 34, where the pitch range extends between approximately 70 Hz and approximately 400 Hz.
37. ~A product comprising:
a machine readable medium; and machine readable instructions embodied on the machine readable medium that:
delay an input signal comprising a fundamental frequency by multiple sample delays to obtain multiple differently delayed input signals;
apply a partitioned adaptive filter comprising multiple individual adaptive filters to the multiple delayed input signals;
generate a filtered output with the partitioned adaptive filter, the filtered output approximately delayed by an integer multiple of the fundamental frequency; and reinforce the input signal with the output estimate.
a machine readable medium; and machine readable instructions embodied on the machine readable medium that:
delay an input signal comprising a fundamental frequency by multiple sample delays to obtain multiple differently delayed input signals;
apply a partitioned adaptive filter comprising multiple individual adaptive filters to the multiple delayed input signals;
generate a filtered output with the partitioned adaptive filter, the filtered output approximately delayed by an integer multiple of the fundamental frequency; and reinforce the input signal with the output estimate.
38. ~The product of claim 37, where the machine readable instructions further:
generate an error signal for each of the multiple individual adaptive filters;
and adapt each of the individual adaptive filters based on the error signal for that individual adaptive filter.
generate an error signal for each of the multiple individual adaptive filters;
and adapt each of the individual adaptive filters based on the error signal for that individual adaptive filter.
39. ~The product of claim 37, where the machine readable instructions further:
bias the estimated fundamental frequency output by a gain parameter.
bias the estimated fundamental frequency output by a gain parameter.
40. ~The product of claim 39, where the gain parameter decreases with increasing signal-to-noise ratio.
41. ~The product of claim 39, where the gain parameter increases with decreasing signal-to-noise ratio.
42. The product of claim 38, where the delay instructions comprise:
D sample delay instructions, where D is selected to implement a maximum adaptation pitch for the multiple adaptive filters.
D sample delay instructions, where D is selected to implement a maximum adaptation pitch for the multiple adaptive filters.
43. The product of claim 42, where the delay instructions further comprise:
L sample delay instructions, where L is selected to implement a pitch tracking range for the multiple adaptive filters.
L sample delay instructions, where L is selected to implement a pitch tracking range for the multiple adaptive filters.
44. The product of claim 43, where the pitch tracking range includes a human voice pitch.
45. The product of claim 43, where the L sample delay instructions implement 'i' series connected sample delay blocks, each of equal length.
46. The product of claim 43, where the L sample delay instructions implement 'i' series connected sample delay blocks, where at least two of the sample delay blocks have different lengths.
47. The product of claim 37, where each of the multiple individual adaptive filters has a filter length of 1.
48. A signal enhancement system comprising:
a signal input;
frequency tracking logic coupled to the signal input and comprising an output, the frequency tracking logic operable to output a fundamental frequency of an input signal;
an adder coupled to the signal input and the output that reinforces the input signal with the fundamental frequency.
a signal input;
frequency tracking logic coupled to the signal input and comprising an output, the frequency tracking logic operable to output a fundamental frequency of an input signal;
an adder coupled to the signal input and the output that reinforces the input signal with the fundamental frequency.
49. The signal enhancement system of claim 48, further comprising delay logic coupled to the signal input and the tracking logic, where the tracking logic outputs the fundamental frequency based on a delayed version of the input signal.
50. The signal enhancement system of claim 48, where the fundamental frequency comprises a frequency occurring in a voice frequency range.
51. The signal enhancement system of claim 48, where the fundamental frequency comprises a fundamental frequency created by a male.
52. The signal enhancement system of claim 48, where the fundamental frequency comprises a voice fundamental frequency created by a female.
53. The signal enhancement system of claim 48, further comprising gain control logic coupled to the output.
54. The signal enhancement system of claim 53, further comprising error estimation logic coupled to the signal input and the output, where the gain control logic reduces a gain applied to the tracking output as error increases.
55. The signal enhancement system of claim 53, further comprising a slowly adapting first stage filter coupled to the signal input.
56. The signal enhancement system of claim 55, where the first stage filter comprises quasi-stationary signal tracking and attenuation logic.
57. A method for enhancing a signal, comprising:
receiving an input signal;
delaying the input signal;
estimating periodicity in the input signal based on a delayed signal; and reinforcing the input signal with the delayed signal.
receiving an input signal;
delaying the input signal;
estimating periodicity in the input signal based on a delayed signal; and reinforcing the input signal with the delayed signal.
58. The method of claim 57, where estimating comprises:
adaptively filtering the delayed signal.
adaptively filtering the delayed signal.
59. The method of claim 57, where adaptively filtering comprises:
applying a filter to the delayed signal; and adapting the filter using Normalized Least Means Squares techniques.
applying a filter to the delayed signal; and adapting the filter using Normalized Least Means Squares techniques.
60. The method of claim 57, further comprising:
outputting a filtered output signal; and determining an error between the filtered output signal and the input signal.
outputting a filtered output signal; and determining an error between the filtered output signal and the input signal.
61. The method of claim 60, where estimating comprises:
adapting the filter coefficients based on the error.
adapting the filter coefficients based on the error.
62. The method of claim 60, further comprising:
adjusting gain applied to the filtered output signal based on the error.
adjusting gain applied to the filtered output signal based on the error.
63. The method of claim 57 where estimating comprises:
estimating a fundamental frequency of the input signal.
estimating a fundamental frequency of the input signal.
64. The method of claim 63, where the fundamental frequency occurs in a voice frequency band.
65. The method of claim 63, where the fundamental frequency is less than approximately 400 Hz.
66. The method of claim 63, where the fundamental frequency is less than approximately 200 Hz.
67. A product comprising:
a machine readable medium; and machine readable instructions embodied on the machine readable medium which cause a processor to perform any the method recited in any of claims 57-66.
a machine readable medium; and machine readable instructions embodied on the machine readable medium which cause a processor to perform any the method recited in any of claims 57-66.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/973,575 US7680652B2 (en) | 2004-10-26 | 2004-10-26 | Periodic signal enhancement system |
| US10/973,575 | 2004-10-26 | ||
| US11/101,796 US8170879B2 (en) | 2004-10-26 | 2005-04-08 | Periodic signal enhancement system |
| US11/101,796 | 2005-04-08 | ||
| US11/102251 | 2005-04-08 | ||
| US11/102,251 US7610196B2 (en) | 2004-10-26 | 2005-04-08 | Periodic signal enhancement system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2524162A1 true CA2524162A1 (en) | 2006-04-26 |
| CA2524162C CA2524162C (en) | 2011-01-11 |
Family
ID=35698847
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2524162A Active CA2524162C (en) | 2004-10-26 | 2005-10-24 | Periodic signal enhancement system |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1653445A1 (en) |
| JP (1) | JP2006126841A (en) |
| KR (1) | KR100754558B1 (en) |
| CA (1) | CA2524162C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9020158B2 (en) | 2008-11-20 | 2015-04-28 | Harman International Industries, Incorporated | Quiet zone control system |
| US8135140B2 (en) | 2008-11-20 | 2012-03-13 | Harman International Industries, Incorporated | System for active noise control with audio signal compensation |
| US8718289B2 (en) | 2009-01-12 | 2014-05-06 | Harman International Industries, Incorporated | System for active noise control with parallel adaptive filter configuration |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4852169A (en) * | 1986-12-16 | 1989-07-25 | GTE Laboratories, Incorporation | Method for enhancing the quality of coded speech |
| KR100300964B1 (en) * | 1999-05-18 | 2001-09-26 | 윤종용 | Speech coding/decoding device and method therof |
-
2005
- 2005-10-21 EP EP05023037A patent/EP1653445A1/en not_active Withdrawn
- 2005-10-24 CA CA2524162A patent/CA2524162C/en active Active
- 2005-10-26 JP JP2005311122A patent/JP2006126841A/en active Pending
- 2005-10-26 KR KR1020050101336A patent/KR100754558B1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| CA2524162C (en) | 2011-01-11 |
| EP1653445A1 (en) | 2006-05-03 |
| KR100754558B1 (en) | 2007-09-05 |
| KR20060049382A (en) | 2006-05-18 |
| JP2006126841A (en) | 2006-05-18 |
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