Compatible signal encode/decode system

• US 5,479,168 A
• Filed: 08/20/1993
• Issued: 12/26/1995
• Est. Priority Date: 05/29/1991
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Pacific Microsonics Inc (Microsoft Corporation)
• Inventors: Johnson, Keith O., Pflaumer, Michael W.
• Primary Examiner(s): Williams, Howard L.
• Application Number:
  US08/110,335
• Time in Patent Office: 858 Days
• Field of Search: 360/32, 341/110, 341/131, 341/139, 341/143, 341/144, 341/155
• US Class Current: 341/110
• CPC Class Codes: G06J 1/00 Hybrid computing arrangements digitally-programmed analogue computers G06G7/06
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: H03M 5/04 the pulses having two levels
• CPC Class Codes: H04B 14/046 Systems or methods for reducing noise or bandwidth

Abstract

An electronic method and apparatus for signal encoding and decoding to provide ultra low distortion reproduction of analog signals, while remaining compatible with industry standardized signal playback apparatus not incorporating the decoding features of the invention, and wherein the improved system provides an interplay of gain, slew rate and wave synthesis operations to reduce signal distortions and improve apparent resolution, all under the control of concealed control codes for triggering appropriate decoding signal reconstruction compensation complementing the signal analysis made during encoding. In addition, signals lacking the encoding process features of the invention are likewise compatible with playback decoders which do embody the invention, to provide some overall restoration enhancement.

Claims

1. A method for converting and encoding analog signals to a standardized digital format, comprising the steps of:

monitoring the physical characteristics of an analog waveform to be converted to a standardized digital format;

converting said analog waveform to said digital format; and

encoding within said standardized digital format information indicative of the physical characteristics of said analog waveform, said information facilitating subsequent more accurate reconstruction of said analog waveform from said standardized digital format without altering the ability to also recover said analog waveform independent of said information.

2. A method as set forth in claim 1, wherein said information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

3. A method as set forth in claim 1, wherein said information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

4. A method as set forth in any of claims 1, 2 or 3, wherein said information is encrypted to the least significant bits of said digital format.

5. A method as set forth in any of claims 1, 2 or 3, wherein said information provides control codes.

6. A method as set forth in claim 4, wherein said information provides control codes.

7. A method as set forth in any of claims 1, 2 or 3 wherein said information is selectively inserted in the least significant bits of said digital format as control codes for prescribed time periods and said least significant bits represent said analog waveform during time periods other than said prescribed time periods.

8. A method as set forth in claim 1, and further including the step of

dispersing within said information, over a period of time, additional analog waveform data as hidden code, whereby the apparent signal spectrum is expanded.

9. A method as set forth in claim 1, and further including the steps of:

interrupting all system operations to create a period of electrical silence;

performing digital sampling of said analog waveform during said period of electrical silence; and

resuming system operations after said digital sampling has been completed.

10. A method as set forth in claim 1, wherein said digital format represents a compressed signal to be complementary expanded by a subsequent decoder.

11. A method as set forth in any of claims 1, 2, 3, 8, 9 or 10, wherein said information relates to slew correction.

12. A method as set forth in claim 4, wherein said information relates to slew correction.

13. A method as set forth in claim 6, wherein said information relates to slew correction.

14. A method as set forth in claim 7, wherein said information relates to slew correction.

15. A method as set forth in any of claims 1, 2, 3, 8, 9 or 10, wherein said information relates to level correction.

16. A method as set forth in claim 4, wherein said information relates to level correction.

17. A method as set forth in claim 6, wherein said information relates to level correction.

18. A method as set forth in claim 7, wherein said information relates to level correction.

19. A method as set forth in any of claims 1, 2, 3, 8, 9 or 10, wherein said information relates to waveform synthesis.

20. A method as set forth in claim 4, wherein said information relates to waveform synthesis.

21. A method as set forth in claim 6, wherein said information relates to waveform synthesis.

22. A method as set forth in claim 7, wherein said information relates to waveform synthesis.

23. A method as set forth in any of claims 1, 2, 3, 8, 9 or 10, wherein said information relates to level, slew and corrective waveform synthesis.

24. A method as set forth in any of claims 1, 2, 3, 8, 9 or 10, wherein said information provides control codes encoded to a random number sequence.

25. A method as set forth in claim 24, wherein said random number sequence modulates the least significant bits of said digital format.

26. A method as set forth in claim 24, and further including the step of processing small signal changes independent of lower frequency average level.

36. A method as set forth in claim 1, including the step of managing said information for optimum encoding processes favoring each signal condition for gain, level, slew rate and waveform synthesis.

27. A method for decoding and converting an encoded digital format signal to an analog waveform;

comprising the steps of;

decoding from said digital format control information indicative of certain specified physical characteristics of said analog waveform;

converting said digital format signal to said analog waveform; and

selectively introducing signal reconstruction compensation, in accordance with said control information during said converting process, whereby said analog waveform can subsequently be more accurately reconstructed from said digital format by utilization of said control information while preserving the ability to recover said analog waveform independent of said control information.

28. A method as set forth in claim 27, wherein said information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

29. A method as set forth in claim 28, wherein said information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

30. A method as set forth in claim 27, wherein said compensation involves slew correction.

31. A method as set forth in claim 27, wherein said compensation involves level correction.

32. A method as set forth in claim 27, wherein said compensation involves waveform synthesis.

33. A method as set forth in any of claim 27 through 32, wherein said control information relates to level, slew and corrective waveform synthesis.

34. A method as set forth in any of claims 27 through 32, wherein said control information is in the form of control codes encoded to a random number sequence.

35. A method as set forth in claim 34, wherein said random number sequence modulates the least significant bits of said digital format.

37. A method for converting a digital format signal to an analog waveform, comprising the steps of:

converting said digital format signal to said analog waveform; and

introducing signal reconstruction compensation, in accordance with said digital format signal during said converting process to facilitate more accurate reconstruction of said analog waveform from said digital format signal, without altering the ability to also recover said analog waveform independent of said signal reconstruction compensation.

38. A method for converting and encoding an analog signal to a standardized digital format and subsequently decoding and converting the digital format to recover the analog signal, comprising the steps of:

monitoring the physical characteristics of an analog waveform to be converted to a standardized digital format;

converting said analog waveform to said digital format;

encoding within said digital format control information indicative of the physical characteristics of said analog waveform, to facilitate subsequent more accurate reconstruction of said analog waveform from said digital format;

decoding from said digital format said control information indicative of certain specified physical characteristics of said analog waveform;

converting said standardized digital format signal to said analog waveform; and

introducing signal reconstruction compensation, in accordance with said control information during said converting process, whereby said analog waveform is subsequently more accurately reconstructed from said digital format without altering the ability to also recover said analog waveform independent of said control information.

39. A method as set forth in claim 38, wherein said information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

40. A method as set forth in claim 38, wherein said information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

41. A method as set forth in any of claims 38, 39 or 40, wherein said control information is encrypted to the least significant bits of said digital format.

42. A method as set forth in claim 41, wherein said control information provides control codes.

43. A method as set forth in claim 38, wherein said digital format represents a compressed signal to be complementary expanded by a subsequent decoding.

44. A method as set forth in any of claims 38, 39, 40 or 43, wherein said control information relates to slew correction.

45. A method as set forth in any of claims 38, 39, 40 or 43, wherein said information relates to level correction.

46. A method as set forth in any of claims 38, 39, 40 or 43, wherein said control information relates to waveform synthesis.

47. A method as set forth in any of claims 38, 39, 40 or 43, wherein said control information relates to level, slew and corrective waveform synthesis.

48. A method as set forth in any of claims 38, 39, 40 or 43, wherein said control information provides control codes encoded to a random number sequence.

49. A method as set forth in claim 48, wherein said random number sequence modulates the least significant bits of said digital format.

50. A method as set forth in any claims 38, 39, 40 or 43, and further including the step of processing small signal changes independent of lower frequency average level.

51. A method as set forth in claim 38, wherein said compensation involves slew correction.

52. A method as set forth in claim 38, wherein said compensation involves level correction.

53. A method as set forth in claim 38, wherein said compensation involves waveform synthesis.

54. A method as set forth in any of claims 38, 39, 40 or 43, wherein said control information relates to level, slew and corrective waveform synthesis.

55. A system for converting and encoding analog signals to a standardized digital format, comprising:

means for monitoring the physical characteristics of an analog waveform to be converted to a standardized digital format;

means for converting said analog waveform to said digital format; and

means for encoding within said digital format information indicative of the physical characteristics of said analog waveform, said information facilitating subsequent more accurate reconstruction of said analog waveform from said standardized digital format without altering the ability to also recover said analog waveform independent of said information.

56. A system as set forth in claim 55, and further including

limiting means for peak limiting said digital format;

and

means for selectively activating said limiting means.

57. A system as set forth in claim 55, wherein said information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

58. A system as set forth in claim 55, wherein said information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

59. A system as set forth in claim 55, wherein said information is encrypted to the least significant bits of said digital format.

60. A system as set forth in claims 55, wherein said information provides control codes.

61. A system as set forth in claim 55, wherein said digital format represents a compressed signal to be complementary expanded by a subsequent decoder.

62. A system as set forth in any of claims 55 through 61, wherein said information relates to slew correction.

63. A system as set forth in any of claims 55 through 61, wherein said information relates to level correction.

64. A system as set forth in any of claims 55 through 61, wherein said information relates to waveform synthesis.

65. A system as set forth in any of claims 55 through 61, wherein said information relates to level, slew and corrective waveform synthesis.

66. A system as set forth in any of claims 55 through 61, wherein said information is in the form of control codes encoded to a random number sequence.

67. A system as set forth in claim 66, wherein said random number sequence modulates the least significant bits of said digital format.

68. A system as set forth in any of claims 55 through 61, and further including means for processing small signal changes independent of lower frequency average level.

69. A system for decoding and converting an encoded digital format signal to an analog waveform;

comprising;

means for extracting from said digital format control information indicative of certain specified physical characteristics of said analog waveform;

means for converting said digital format signal to said analog waveform; and

means for introducing signal reconstruction compensation, in accordance with said control information during said converting process, whereby said analog waveform is subsequently more accurately reconstructed from said digital format without altering the ability to also recover said analog waveform independent of said control information.

70. A system as set forth in claim 69, wherein said control information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

71. A system as set forth in claim 70, wherein said control information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

72. A system as set forth in claim 69, wherein said compensation involves slew correction.

73. A system as set forth in claim 69, wherein said compensation involves level correction.

74. A system as set forth in claim 69, wherein said compensation involves waveform synthesis.

75. A system as set forth in any of claim 69 through 74, wherein said control information relates to level, slew and corrective waveform synthesis.

76. A system as set forth in any of claims 69 through 74, wherein said control information is in the form of control codes encoded to a random number sequence.

77. A system as set forth in claim 76, wherein said random number sequence modulates the least significant bits of said digital format.

78. A system for converting and encoding an analog signal to a standardized digital format and subsequently decoding and converting said digital formal to recover the analog signal, comprising:

means for monitoring the physical characteristics of an analog waveform to be converted to a standardized digital format;

means for converting said analog waveform to said digital format;

means for encoding within said digital format control information indicative of the physical characteristics of said analog waveform, to facilitate subsequent more accurate reconstruction of said analog waveform from said digital format;

means for decoding from said digital format said control information indicative of certain specified physical characteristics of said analog waveform;

means for converting said digital format signal to said analog waveform; and

means for introducing signal reconstruction compensation, in accordance with said control information during said converting process, whereby said analog waveform is subsequently more accurately reconstructed from said digital format without altering the ability to also recover said analog waveform independent of said control information.

79. A system as set forth in claim 78, wherein said control information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

80. A system as set forth in claim 79, wherein said control information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

81. A system as set forth in claim 78, wherein said signal reconstruction compensation involves slew correction.

82. A system as set forth in claim 78, wherein said signal reconstruction compensation involves level correction.

83. A system as set forth in claim 78, wherein said signal reconstruction compensation involves waveform synthesis.

84. A system as set forth in claim 78, wherein said control information relates to level, slew and corrective waveform synthesis.

85. A system as set forth in claim 78, wherein said control information provides control codes encoded to a random number sequence.

86. A system as set forth in claim 85, wherein said random number sequence modulates the least significant bits of said digital format.

87. In a system for encoding and decoding signals in a standardized format, the improvement comprising:

means for generating a dithering signal;

means for combining said dithering signal with the signal being encoded;

means for encrypting additional control signals relating to characteristics of said signal being encoded in said dithering signal to facilitate more accurate reconstruction of said signal being encoded from the encoded format without altering the ability to also recover said signal being encoded independent of said control signals.

88. A recording product having recorded thereon an analog signal waveform encoded in a standardized digital format, said product comprising:

a recording medium having recorded thereon said analog waveform converted to said digital format and further including within said digital format encoded information indicative of the physical characteristics of said analog waveform, said information facilitating subsequent more accurate reconstruction of said analog waveform from said standardized digital format without altering the ability to also recover said analog waveform independent of said information.

89. A recording product as set forth in claim 88, wherein said information indicative of the physical characteristics of said analog waveform is encrypted within said digital format.

90. A recording product as set forth in claim 88, wherein said information indicative of the physical characteristics of said analog waveform is concealed within said digital format.

91. A recording product as set forth in any of claims 88, 89 or 90, wherein said information is encrypted to the least significant bits of said digital format.

92. A recording product as set forth in any of claims 88, 89, or 90, wherein said information provides process control codes.

93. A recording product as set forth in claim 88, wherein said digital format represents a compressed signal to be complementary expanded by a subsequent decoder.

94. A recording product as set forth in claim 88, wherein said digital format represents a peak limited signal for high signal levels and an expanded signal for low signal levels.

95. A recording product as set forth in claim 88, wherein said information relates to slew correction.

96. A recording product as set forth in claim 88, wherein said information relates to level correction.

97. A recording product as set forth in claim 88, wherein said information relates to waveform synthesis.

98. A recording product as set forth in claim 88, wherein said information relates to level, slew and corrective waveform synthesis.

99. A recording product as set forth in claim 88, wherein said information provides process control codes encoded to a random number sequence.

100. A recording product as set forth in claim 99, wherein said random number sequence is recorded as modulation of the least significant bits of said digital format.