1. A method for post-processing a decoded sound signal in view of enhancing a perceived quality of said decoded sound signal, comprising:
dividing the decoded sound signal into a plurality of frequency sub-band signals; and
applying post-processing to only a part of the frequency sub-band signals;
wherein applying post-processing to only a part of the frequency sub-band signals comprises pitch enhancing the frequency sub-band signals only in a lower frequency band of the decoded sound signal.', 'dividing the decoded sound signal into a plurality of frequency sub-band signals; and', 'applying post-processing to only a part of the frequency sub-band signals;', 'wherein applying post-processing to only a part of the frequency sub-band signals comprises pitch enhancing the frequency sub-band signals only in a lower frequency band of the decoded sound signal.

2. A post-processing method as defined in claim 1, further comprising summing the frequency sub-band signals, after post-processing of said part of the frequency sub-band signals, to produce an output post-processed decoded sound signal.

3. A post-processing method as defined in claim 1, wherein pitch enhancing comprises adaptively filtering said part of the frequency sub-band signals.

4. A post-processing method as defined in claim 1, wherein dividing the decoded sound signal into a plurality of frequency sub-band signals comprises sub-band filtering the decoded sound signal to produce the plurality of frequency sub-band signals.

5. A post-processing method as defined in claim 1, wherein, for said part of the frequency sub-band signals:
pitch enhancing comprises adaptively filtering the decoded sound signal; and
dividing the decoded sound signal comprises sub-band filtering the adaptively filtered decoded sound signal.', 'pitch enhancing comprises adaptively filtering the decoded sound signal; and', 'dividing the decoded sound signal comprises sub-band filtering the adaptively filtered decoded sound signal.

6. A post-processing method as defined in claim 1, wherein:
dividing the decoded sound signal into a plurality of frequency sub-band signals comprises:
a high-pass filtering of the decoded sound signal to produce a frequency high-band signal; and
a first low-pass filtering of the decoded sound signal to produce a frequency low-band signal; and
pitch enhancing comprises:
pitch enhancing the decoded sound signal prior to the first low-pass filtering of the decoded sound signal to produce the frequency low-band signal.', 'dividing the decoded sound signal into a plurality of frequency sub-band signals comprises:', 'a high-pass filtering of the decoded sound signal to produce a frequency high-band signal; and', 'a first low-pass filtering of the decoded sound signal to produce a frequency low-band signal; and', 'pitch enhancing comprises:', 'pitch enhancing the decoded sound signal prior to the first low-pass filtering of the decoded sound signal to produce the frequency low-band signal.

7. A post-processing method as defined in claim 6, further comprising a second low-pass filtering of the decoded sound signal prior to pitch enhancing said decoded sound signal.

8. A post-processing method as defined in claim 6, further comprising summing the frequency high-band and low-band signals to produce an output post-processed decoded sound signal.

9. A post-processing method as defined in claim 1, wherein:
dividing the decoded sound signal into a plurality of frequency sub-band signals comprises:
band-pass filtering the decoded sound signal to produce a frequency upper-band signal; and
low-pass filtering the decoded sound signal to produce a frequency lower-band signal; and
pitch enhancing comprises:
pitch enhancing the decoded sound signal prior to low-pass filtering the decoded sound signal to produce a frequency lower-band signal.', 'dividing the decoded sound signal into a plurality of frequency sub-band signals comprises:', 'band-pass filtering the decoded sound signal to produce a frequency upper-band signal; and', 'low-pass filtering the decoded sound signal to produce a frequency lower-band signal; and', 'pitch enhancing comprises:', 'pitch enhancing the decoded sound signal prior to low-pass filtering the decoded sound signal to produce a frequency lower-band signal

10. A post-processing method as defined in claim 9, further comprising summing the frequency upper-band and lower-band signals to produce an output post-processed decoded sound signal

11. A post-processing method as defined in claim 1, wherein:
dividing the decoded sound signal into a plurality of frequency sub-band signals comprises:
low-pass filtering the decoded sound signal to produce a frequency low-band signal; and
pitch enhancing comprises:
pitch enhancing the frequency low-band signal.', 'dividing the decoded sound signal into a plurality of frequency sub-band signals comprises:', 'low-pass filtering the decoded sound signal to produce a frequency low-band signal; and', 'pitch enhancing comprises:', 'pitch enhancing the frequency low-band signal

12. A post-processing method as defined in claim 11, wherein pitch enhancing comprises processing the decoded sound signal through an inter-harmonic filter for inter-harmonic attenuation of the decoded sound signal

13. A post-processing method as defined in claim 12, wherein pitch enhancing comprises multiplying the inter-harmonic filtered decoded sound signal by an adaptive pitch enhancement gain

14. A post-processing method as defined in claim 12, further comprising low-pass filtering the decoded sound signal prior to processing the decoded sound signal through the inter-harmonic filter

15. A post-processing method as defined in claim 11, further comprising summing the decoded sound signal and the frequency low-band signal to produce an output post-processed decoded sound signal

16. A post-processing method as defined in claim 11, wherein pitch enhancing comprises processing the decoded sound signal through an inter-harmonic filter having the following transfer function:', 'y
âx81¡


n



=



1
2

âx81¢

x
âx81¡


n




-


1
4

âx81¢

{


x
âx81¡



n
-
T




+

x
âx81¡



n
+
T





}', 'for inter-harmonic attenuation of the decoded sound signal, where xn is the decoded sound signal, yn is the inter-harmonic filtered decoded sound signal in a given sub-band, and T is a pitch delay of the decoded sound signal

17. A post-processing method as defined in claim 16, further comprising summing the unprocessed decoded sound signal and the inter-harmonic filtered frequency low-band signal to produce an output post-processed decoded sound signal

18. A post-processing method as defined in claim 1, wherein pitch enhancing comprises pitch enhancing the decoded sound signal using the following equation:', 'y
âx81¡


n



=



(

1
-

α
2


)

âx81¢

x
âx81¡


n




+


α
4

âx81¢

{


x
âx81¡



n
-
T




+

x
âx81¡



n
+
T





}', 'where xn is the decoded sound signal, yn is the pitch enhanced decoded sound signal in a given sub-band, T is a pitch delay of the decoded sound signal, and α is a coefficient varying between 0 and 1 to control an amount of inter-harmonic attenuation of the decoded sound signal

19. A post-processing method as defined in claim 18, comprising receiving the pitch delay T through a bitstream.

20. A post-processing method as defined in claim 18, comprising decoding the pitch delay T from a received, encoded bitstream.

21. A post-processing method as defined in claim 18, comprising calculating the pitch delay T in response to the decoded sound signal for an improved pitch tracking.

22. A post-processing method as defined in claim 1, wherein, during encoding, the sound signal is down-sampled from a higher sampling frequency to a lower sampling frequency, and wherein dividing the decoded sound signal into a plurality of frequency sub-band signals comprises up-sampling the decoded sound signal from the lower sampling frequency to the higher sampling frequency.

23. A post-processing method as defined in claim 22, wherein dividing the decoded sound signal into a plurality of frequency sub-band signals comprises sub-band filtering the decoded sound signal, and wherein the up-sampling of the decoded sound signal from the lower sampling frequency to the higher sampling frequency is combined to the sub-band filtering.

24. A post-processing method as defined in claim 22, comprising:
band-pass filtering the decoded sound signal to produce a frequency upper-band signal, said band-pass filtering of the decoded sound signal being combined with up-sampling of the decoded sound signal from the lower sampling frequency to the higher sampling frequency; and
pitch enhancing the decoded sound signal and low-pass filtering the pitch enhanced decoded sound signal to produce a frequency lower-band signal, said low-pass filtering of the pitch enhanced decoded sound signal being combined with up-sampling of the post-processed decoded sound signal from the lower sampling frequency to the higher sampling frequency.', 'band-pass filtering the decoded sound signal to produce a frequency upper-band signal, said band-pass filtering of the decoded sound signal being combined with up-sampling of the decoded sound signal from the lower sampling frequency to the higher sampling frequency; and', 'pitch enhancing the decoded sound signal and low-pass filtering the pitch enhanced decoded sound signal to produce a frequency lower-band signal, said low-pass filtering of the pitch enhanced decoded sound signal being combined with up-sampling of the post-processed decoded sound signal from the lower sampling frequency to the higher sampling frequency.

25. post-processing method as defined in claim 24, further comprising adding the frequency upper-band signal with the frequency lower-band signal to form an output post-processed and up-sampled decoded sound signal.

26. A post-processing method as defined in claim 24, wherein pitch enhancing the decoded sound signal comprises processing the decoded sound signal by means of the following equation:', 'y
âx81¡


n



=



(

1
-

α
2


)

âx81¢

x
âx81¡


n




+


α
4

âx81¢

{


x
âx81¡



n
-
T




+

x
âx81¡



n
+
T





}', 'where xn is the decoded sound signal, yn is the pitch enhanced decoded sound signal in a given sub-band, T is a pitch delay of the decoded sound signal, and α is a coefficient varying between 0 and 1 to control an amount of inter-harmonic attenuation of the decoded sound signal.

27. A post-processing method as defined in claim 1, wherein:
dividing the decoded sound signal into a plurality of frequency sub-band signals comprises dividing the decoded sound signal into a frequency upper-band signal and a frequency lower-band signal; and
pitch enhancing comprises pitch enhancing the frequency lower-band signal.', 'dividing the decoded sound signal into a plurality of frequency sub-band signals comprises dividing the decoded sound signal into a frequency upper-band signal and a frequency lower-band signal; and', 'pitch enhancing comprises pitch enhancing the frequency lower-band signal.

28. A post-processing method as defined in claim 1, wherein pitch enhancing comprises:
determining a pitch value of the decoded sound signal;
calculating, in relation to the determined pitch value, a high-pass filter with a cut-off frequency below a fundamental frequency of the decoded sound signal; and
processing the decoded sound signal through the calculated high-pass filter.', 'determining a pitch value of the decoded sound signal;', 'calculating, in relation to the determined pitch value, a high-pass filter with a cut-off frequency below a fundamental frequency of the decoded sound signal; and', 'processing the decoded sound signal through the calculated high-pass filter.

29. A device for post-processing a decoded sound signal in view of enhancing a perceived quality of said decoded sound signal, comprising:
a divider of the decoded sound signal into a plurality of frequency sub-band signals; and
a post-processor of only a part of the frequency sub-band signals;
wherein the post-processor comprises a pitch enhancer of the frequency sub-band signals only in a lower frequency band of the decoded sound signal.', 'a divider of the decoded sound signal into a plurality of frequency sub-band signals; and', 'a post-processor of only a part of the frequency sub-band signals;', 'wherein the post-processor comprises a pitch enhancer of the frequency sub-band signals only in a lower frequency band of the decoded sound signal.

30. A post-processing device as defined in claim 29, further comprising an adder for summing the frequency sub-band signals, after post-processing of said part of the frequency sub-band signals, to produce an output post-processed decoded sound signal.

31. A post-processing device as defined in claim 29, wherein the post-processor comprises an adaptive filter supplied with the decoded sound signal.

32. A post-processing device as defined in claim 29, wherein the divider comprises a sub-band filter supplied with the decoded sound signal.

33. A post-processing device as defined in claim 29, wherein, for said part of the frequency sub-band signals:
the post-processor comprises an adaptive filter supplied with the decoded sound signal to produce an adaptively filtered decoded sound signal; and
the dividing means comprises a sub-band filter supplied with the adaptively filtered decoded sound signal.', 'the post-processor comprises an adaptive filter supplied with the decoded sound signal to produce an adaptively filtered decoded sound signal; and', 'the dividing means comprises a sub-band filter supplied with the adaptively filtered decoded sound signal.

34. A post-processing device as defined in claim 29, wherein:
the dividing means comprises:
a high-pass filter supplied with the decoded sound signal to produce a frequency high-band signal; and
a first low-pass filter supplied with the decoded sound signal to produce a frequency low-band signal; and
the pitch enhancer enhances the decoded sound signal prior to low-pass filtering the decoded sound signal through the first low-pass filter.', 'the dividing means comprises:', 'a high-pass filter supplied with the decoded sound signal to produce a frequency high-band signal; and', 'a first low-pass filter supplied with the decoded sound signal to produce a frequency low-band signal; and', 'the pitch enhancer enhances the decoded sound signal prior to low-pass filtering the decoded sound signal through the first low-pass filter.

35. A post-processing device as defined in claim 34, wherein the post-processor further comprises a second low-pass filter supplied with the decoded sound signal to produce a low-pass filtered decoded sound signal supplied to the pitch enhancer.

36. A post-processing device as defined in claim 34,further comprising an adder for summing the frequency high-band and low-band signals to produce an output post-processed decoded sound signal.

37. A post-processing device as defined in claim 29, wherein:
the divider comprises:
a band-pass filter supplied with the decoded sound signal to produce a frequency upper-band signal; and
a low-pass filter supplied with the decoded sound signal to produce a frequency lower-band signal; and
the pitch enhancer enhances the decoded sound signal prior to low-pass filtering the decoded sound signal through the low-pass filter to produce the frequency lower-band signal.', 'the divider comprises:', 'a band-pass filter supplied with the decoded sound signal to produce a frequency upper-band signal; and', 'a low-pass filter supplied with the decoded sound signal to produce a frequency lower-band signal; and', 'the pitch enhancer enhances the decoded sound signal prior to low-pass filtering the decoded sound signal through the low-pass filter to produce the frequency lower-band signal.

38. A post-processing device as defined in claim 37, wherein the pitch enhancer comprises a pitch filter supplied with the decoded sound signal to produce a pitch enhanced decoded sound signal supplied to the low-pass filter.

39. A post-processing device as defined in claim 37, further comprising an adder for summing the frequency upper-band and lower-band signals to produce an output post-processed decoded sound signal.

40. A post-processing device as defined in claim 29, wherein: the divider comprises:
a low-pass filter supplied with the decoded sound signal to produce a frequency low-band signal; and
the pitch enhancer enhances the decoded sound signal to produce a post-processed pitch enhanced decoded sound signal supplied to the low-pass filter.', 'a low-pass filter supplied with the decoded sound signal to produce a frequency low-band signal; and', 'the pitch enhancer enhances the decoded sound signal to produce a post-processed pitch enhanced decoded sound signal supplied to the low-pass filter.

41. A post-processing device as defined in claim 40, wherein the pitch enhancer comprises an inter-harmonic filter supplied with the decoded sound signal to produce an inter-harmonic, attenuated decoded sound signal.

42. A post-processing device as defined in claim 41, wherein the pitch enhancer comprises a multiplier for multiplying the inter-harmonic, attenuated decoded sound signal by an adaptive pitch enhancement gain.

43. A post-processing device as defined in claim 41, further comprising a low-pass filter supplied with the decoded sound signal to produce a low-pass filtered decoded sound signal supplied to the inter-harmonic filter.

44. A post-processing device as defined in claim 40, further comprising an adder for summing the decoded sound signal and the frequency low-band signal to produce an output post-processed decoded sound signal.

45. A post-processing device as defined in claim 40, wherein the pitch enhancer comprises an inter-harmonic filter having the following transfer function:', 'y
âx81¡


n



=



1
2

âx81¢

x
âx81¡


n




-


1
4

âx81¢

{


x
âx81¡



n
-
T




+

x
âx81¡



n
+
T





}', 'for inter-harmonic attenuating the decoded sound signal, where xn is the decoded sound signal, yn is the inter-harmonic filtered decoded sound signal in a given sub-band, and T is a pitch delay of the decoded sound signal.

46. A post-processing device as defined in claim 45, further comprising an adder for summing the unprocessed decoded sound signal and the inter-harmonic filtered frequency low-band signal to produce an output post-processed decoded sound signal.

47. A post-processing device as defined in claim 29, wherein the pitch enhancer of the decoded sound signal uses the following equation:', 'y
âx81¡


n



=



(

1
-

α
2


)

âx81¢

x
âx81¡


n




+


α
4

âx81¢

{


x
âx81¡



n
-
T




+

x
âx81¡



n
+
T





}', 'where xn is the decoded sound signal, yn is the pitch enhanced decoded sound signal in a given sub-band, T is a pitch delay of the decoded sound signal, and α is a coefficient varying between 0 and 1 to control an amount of inter-harmonic attenuation of the decoded sound signal.

48. A post-processing device as defined in claim 47, comprising a receiver of the pitch delay T through a bitstream.

49. A post-processing device as defined in claim 47, comprising a decoder of the pitch delay T from a received, encoded bitstream.

50. A post-processing device as defined in claim 47, comprising a calculator of the pitch delay T in response to the decoded sound signal for an improved pitch tracking.

51. A post-processing device as defined in claim 29, wherein, during encoding, the sound signal is down-sampled from a higher sampling frequency to a lower sampling frequency, and wherein the divider comprises an up-sampler of the decoded sound signal from the lower sampling frequency to the higher sampling frequency.

52. A post-processing device as defined in claim 51, wherein the divider comprises a sub-band filter supplied with the decoded sound signal, and wherein the up-sampler is combined with the sub-band filter.

53. A post-processing device as defined in claim 51, wherein:
the pitch enhancer enhances the decoded sound signal; and
the divider comprises:
a band-pass filter supplied with the decoded sound signal to produce a frequency upper-band signal, said band-pass filter being combined with the up-sampler; and
a low-pass filter supplied with the pitch enhanced decoded sound signal to produce a frequency lower-band signal, said low-pass filter being combined with the up-sampler.', 'the pitch enhancer enhances the decoded sound signal; and', 'the divider comprises:', 'a band-pass filter supplied with the decoded sound signal to produce a frequency upper-band signal, said band-pass filter being combined with the up-sampler; and', 'a low-pass filter supplied with the pitch enhanced decoded sound signal to produce a frequency lower-band signal, said low-pass filter being combined with the up-sampler.

54. A post-processing device as defined in claim 53, further comprising an adder for summing the frequency upper-band signal with the frequency lower-band signal to form an output pitch-enhanced and up-sampled decoded sound signal.

55. A post-processing device as defined in claim 53, wherein the pitch enhancer uses the following equation:', 'y
âx81¡


n



=



(

1
-

α
2


)

âx81¢

x
âx81¡


n




+


α
4

âx81¢

{


x
âx81¡



n
-
T




+

x
âx81¡



n
+
T





}', 'where xn is the decoded sound signal, yn is the pitch enhanced decoded sound signal in a given sub-band, T is a pitch delay of the decoded sound signal, and α is a coefficient varying between 0 and 1 to control an amount of inter-harmonic attenuation of the decoded sound signal.

56. A post-processing device as defined in claim 29, wherein:
the divider divides the decoded sound signal into a frequency upper-band signal and a frequency lower-band signal; and
the pitch enhancer enhances the frequency lower-band signal.', 'the divider divides the decoded sound signal into a frequency upper-band signal and a frequency lower-band signal; and', 'the pitch enhancer enhances the frequency lower-band signal.

57. A post-processing device as defined in claim 29, wherein the pitch enhancer:
determines a pitch value of the decoded sound signal;
calculates, in relation to the determined pitch value, a high-pass filter with a cut-off frequency below a fundamental frequency of the decoded sound signal; and
processes the decoded sound signal through the calculated high-pass filter.', 'determines a pitch value of the decoded sound signal;', 'calculates, in relation to the determined pitch value, a high-pass filter with a cut-off frequency below a fundamental frequency of the decoded sound signal; and', 'processes the decoded sound signal through the calculated high-pass filter.

58. A sound signal decoder comprising:
an input for receiving an encoded sound signal;
a parameter decoder supplied with the encoded sound signal for decoding sound signal encoding parameters;
a sound signal decoder supplied with the decoded sound signal encoding parameters for producing a decoded sound signal; and
a post-processing device as recited in any of claims 29 to 57 for post-processing the decoded sound signal in view of enhancing a perceived quality of said decoded sound signal.', 'an input for receiving an encoded sound signal;', 'a parameter decoder supplied with the encoded sound signal for decoding sound signal encoding parameters;', 'a sound signal decoder supplied with the decoded sound signal encoding parameters for producing a decoded sound signal; and', 'a post-processing device as recited in any of claims 29 to 57 for post-processing the decoded sound signal in view of enhancing a perceived quality of said decoded sound signal.']