Methods and apparatus for encoding and decoding signals, methods for transmitting signals, and an information recording medium

• US 5,758,020 A
• Filed: 04/19/1995
• Issued: 05/26/1998
• Est. Priority Date: 04/22/1994
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tsutsui, Kyoya
• Primary Examiner(s): MacDonald, Allen R.
• Assistant Examiner(s): Wieland, Susan
• Application Number:
  US08/424,190
• Time in Patent Office: 1,133 Days
• Field of Search: 395/2.38, 395/2.12, 395/213, 395/2.34, 395/2.67
• US Class Current: 704/204
• CPC Class Codes: H03M 7/3053 Block-companding PCM systems

Abstract

A method for encoding the information has a forward inverse transform step of forward orthogonal transforming an input signal using a pre-set windowing function to form an output spectral signal, and an encoding step of encoding the resulting output spectral signal from the forward orthogonal transform. The preset windowing function having a smaller slope of a characteristic curve at both skirt ends is employed. This allows efficient encoding when employing a transform constituting a waveform signal by overlapping waveform elements with both neighboring waveform elements for generating a waveform signal during inverse orthogonal transform, such as MDCT.

Claims

1. A method for encoding signals, comprising the steps of:

forward orthogonally transforming an input signal using a pre-set windowing function to form an output spectral signal; and

encoding the output spectral signal,

wherein the pre-set windowing function is represented by the equation ##EQU5## where w(n) is the windowing function, p is a value in the vicinity of 2, and M is the number of output spectral components.

2. The method as claimed in claim 1, wherein the forward orthogonal transform is the forward orthogonal transform of overlapping waveform elements of a time block with those of a neighboring block.

3. The method as claimed in claim 2, wherein the forward orthogonal transform is a modified discrete cosine transform.

4. The method as claimed in claim 1, wherein the pre-set windowing function does not include a domain having a zero value.

5. The method as claimed in claim 1, wherein the pre-set windowing function includes a domain having a zero value.

6. The method as claimed in claim 1, wherein the pre-set windowing function has a symmetrical shape.

7. The method as claimed in claim 1, wherein the pre-set windowing function has an asymmetrical shape.

8. The method as claimed in claim 1 wherein the input signal is an acoustic signal.

9. An apparatus for encoding signals, comprising:

means for forward orthogonally transforming an input signal using a pre-set windowing function to form an output spectral signal; and

means for encoding the output spectral signal,

wherein the pre-set windowing function is represented by the equation ##EQU6## where w(n) is the windowing function, p is a value in the vicinity of 2, and M is the number of output spectral components.

10. The apparatus as claimed in claim 9, wherein the forward orthogonal transform is the forward orthogonal transform of overlapping waveform elements of a time block with those of a neighboring block.

11. The apparatus as claimed in claim 9, wherein the forward orthogonal transform is a modified discrete cosine transform.

12. The apparatus as claimed in claim 9, wherein the pre-set windowing function does not include a domain having a zero value.

13. The apparatus as claimed in claim 9, wherein the pre-set windowing function includes a domain having a zero value.

14. The apparatus as claimed in claim 9, wherein the pre-set windowing function has a symmetrical shape.

15. The apparatus as claimed in claim 9, wherein the pre-set windowing function has an asymmetrical shape.

16. The apparatus as claimed in claim 9, wherein the input signal is an acoustic signal.

17. A method for decoding signals, comprising the steps of:

decoding an encoded signal encoded by a pre-set function for outputting a spectral signal; and

inverse orthogonally transforming the spectral signal using a pre-set windowing function, wherein the pre-set windowing function is represented by the equation ##EQU7## where w(n) is the windowing function, p is a value in the vicinity of 2, and M is the number of output spectral components.

18. The method as claimed in claim 17, wherein the inverse orthogonal transform is the inverse orthogonal transform of overlapping waveform elements of a time block with those of a neighboring block.

19. The method as claimed in claim 17, wherein the orthogonal transform is an inverse modified discrete cosine transform.

20. The method as claimed in claim 17, wherein the pre-set windowing function does not include a domain having a zero value.

21. The method as claimed in claim 17, wherein the pre-set windowing function includes a domain having a zero value.

22. The method as claimed in claim 17, wherein the pre-set windowing function has a symmetrical shape.

23. The method as claimed in claim 17, wherein the pre-set windowing function has an asymmetrical shape.

24. The method as claimed in claim 17, wherein the input signal is an acoustic signal.

25. An apparatus for decoding signals, comprising:

means for decoding an encoded signal encoded by a pre-set function for outputting a spectral signal; and

means for inverse orthogonally transforming the spectral signal using a pre-set windowing function, wherein the pre-set windowing function is represented by the equation ##EQU8## where w(n) is the windowing function, p is a value in the vicinity of 2, and M is the number of output spectral components.

26. The apparatus as claimed in claim 25, wherein the inverse orthogonal transform is the inverse orthogonal transform of overlapping waveform elements of a time block with those of a neighboring block.

27. The apparatus as claimed in claim 25, wherein the inverse orthogonal transform is an inverse modified discrete cosine transform.

28. The apparatus as claimed in claim 25, wherein the pre-set windowing function does not include a domain having a zero value.

29. The apparatus as claimed in claim 25, wherein the pre-set windowing function includes the domain having a zero value.

30. The apparatus as claimed in claim 25, wherein the pre-set windowing function has a symmetrical shape.

31. The apparatus as claimed in claim 25, wherein the pre-set windowing function has an asymmetrical shape.

32. The apparatus as claimed in claim 25, wherein the input signal is an acoustic signal.

33. An information recording medium, wherein signals are produced by forward orthogonally transforming an input signal to form an output spectral signal using a pre-set windowing function represented by the equation ##EQU9## where w(n) is the windowing function, p is a value in the vicinity of 2, and M is the number of output spectral components, and by encoding the output spectral signal.

34. The information recording medium as claimed in claim 33, wherein the inverse orthogonal transform is the inverse orthogonal transform of overlapping waveform elements of a time block with those of a neighboring block.

35. The information recording medium as claimed in claim 33, wherein the inverse orthogonal transform is an inverse modified discrete cosine transform.

36. The information recording medium as claimed in claim 33, wherein the pre-set windowing function does not include a domain having a zero value.

37. The information recording medium as claimed in claim 33, wherein the pre-set windowing function includes a domain having a zero value.

38. The information recording medium as claimed in claim 33, wherein the pre-set windowing function has a symmetrical shape.

39. The information recording medium as claimed in claim 33, wherein the pre-set windowing function has an asymmetrical shape.

40. The information recording medium as claimed in claim 33, wherein the input signal is an acoustic signal.

41. A method for transmitting signals, comprising the steps of:

forward orthogonally transforming an input signal to produce an output spectral signal using a pre-set windowing function having characteristics represented by the equation ##EQU10## where w(n) is the windowing function, p is a value in the vicinity of 2, and M is the number of output spectral components; and

transmitting the output spectral signal.

42. The method as claimed in claim 41, wherein the inverse orthogonal transform is the inverse orthogonal transform of overlapping waveform elements of a time block with those of a neighboring block.

43. The method as claimed in claim 41, wherein the orthogonal transform is an inverse modified discrete transform.

44. The method as claimed in claim 41, wherein the pre-set windowing function does not include a domain having a zero value.

45. The method as claimed in claim 41, wherein the pre-set windowing function includes a domain having a zero value.

46. The method as claimed in claim 41, wherein the pre-set windowing function has a symmetrical shape.

47. The method as claimed in claim 41, wherein the pre-set windowing function has an asymmetrical shape.

48. The method as claimed in claim 41, wherein the input signal is an acoustic signal.