SYSTEMS, METHODS, AND APARATUS FOR DYNAMIC NORMALIZATION TO REDUCE LOSS IN PRECISION FOR LOW-LEVEL SIGNALS

• US 20080162126A1
• Filed: 01/30/2008
• Published: 07/03/2008
• Est. Priority Date: 12/04/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rajendran, Vivek, Kandhadai, Ananthapadmanabhan A.
• Granted Patent: US 8,126,708 B2
• Time in Patent Office: Days
• US Class Current: 704/224
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 21/00 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 G10L19/00 takes precedence
• CPC Class Codes: G10L 21/0388 Details of processing therefor

Abstract

A normalization factor for a current frame of a signal may be determined. The normalization factor may depend on an amplitude of the current frame of the signal. The normalization factor may also depend on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal. The current frame of the signal may be normalized based on the normalization factor that is determined. The states'"'"' normalization factor may be adjusted based on the normalization factor that is determined.

Claims

1. An apparatus that is configured for dynamic normalization to reduce loss in precision for low-level signals, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being executable to;

determine a normalization factor for a current frame of a signal, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal;

normalize the current frame of the signal based on the normalization factor that is determined; and

adjust the states'"'"' normalization factor based on the normalization factor that is determined.

2. The apparatus of claim 1, wherein the non-linear values are squared values.

3. The apparatus of claim 1, wherein the non-linear values are cubic values.

4. The apparatus of claim 1, wherein the normalization factor is selected so that saturation does not occur.

5. The apparatus of claim 1, wherein the apparatus is a handset.

6. The apparatus of claim 5, wherein the apparatus is a handset implementing wireless communications.

8. The apparatus of claim 1, wherein the apparatus is a base station.

9. The apparatus of claim 1, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of a synthesis filter, and where the synthesis filter derives an output synthesized speech signal from the normalized low band excitation signal.

10. The apparatus of claim 1, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of high-band excitation generator, and wherein the high-band excitation generator derives a high-band excitation signal from the normalized low band excitation signal.

11. The apparatus of claim 1, wherein the signal is an input speech signal, wherein the normalized signal is a normalized input speech signal, wherein the states are filter states of an analysis filterbank, and wherein the analysis filterbank derives an output signal from the normalized input speech signal.

12. The apparatus of claim 1, wherein the signal is a high band excitation signal, wherein the normalized signal is a normalized high band signal, wherein the states are filter states of a synthesis filterbank, and wherein the synthesis filterbank derives an output signal from the normalized high band signal.

13. A method for dynamic normalization to reduce loss in precision for low-level signals, comprising:

determining a normalization factor for a current frame of a signal, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal;

normalizing the current frame of the signal based on the normalization factor that is determined; and

adjusting the states'"'"' normalization factor based on the normalization factor that is determined.

14. The method of claim 13, wherein the non-linear values are squared values.

15. The method of claim 13, wherein the non-linear values are cubic values.

16. The method of claim 13, wherein the normalization factor is selected so that saturation does not occur.

17. The method of claim 13, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of a synthesis filter, and where the synthesis filter derives an output synthesized speech signal from the normalized low band excitation signal.

18. The method of claim 13, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of high-band excitation generator, and wherein the high-band excitation generator derives a high-band excitation signal from the normalized low band excitation signal.

19. The method of claim 13, wherein the signal is an input speech signal, wherein the normalized signal is a normalized input speech signal, wherein the states are filter states of an analysis filterbank, and wherein the analysis filterbank derives an output signal from the normalized input speech signal.

20. The method of claim 13, wherein the signal is a high band signal, wherein the normalized signal is a normalized high band signal, wherein the states are filter states of a synthesis filterbank, and wherein the synthesis filterbank derives an output signal from the normalized high band signal.

21. An apparatus that is configured for dynamic normalization to reduce loss in precision for low-level signals, comprising:

means for determining a normalization factor for a current frame of a signal, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal;

means for normalizing the current frame of the signal based on the normalization factor that is determined; and

means for adjusting the states'"'"' normalization factor based on the normalization factor that is determined.

22. The apparatus of claim 21, wherein the non-linear values are squared values.

23. The apparatus of claim 21, wherein the non-linear values are cubic values.

24. The apparatus of claim 21, wherein the normalization factor is selected so that saturation does not occur.

25. The apparatus of claim 21, wherein the apparatus is a handset.

26. The apparatus of claim 25, wherein the apparatus is a handset implementing wireless communications.

27. The apparatus of claim 21, wherein the apparatus is a base station.

28. The apparatus of claim 21, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of a synthesis filter, and where the synthesis filter derives an output synthesized speech signal from the normalized low band excitation signal.

29. The apparatus of claim 21, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of high-band excitation generator, and wherein the high-band excitation generator derives a high-band excitation signal from the normalized low band excitation signal.

30. The apparatus of claim 21, wherein the signal is an input speech signal, wherein the normalized signal is a normalized input speech signal, wherein the states are filter states of an analysis filterbank, and wherein the analysis filterbank derives an output signal from the normalized input speech signal.

31. The apparatus of claim 21, wherein the signal is a high band excitation signal, wherein the normalized signal is a normalized high band signal, wherein the states are filter states of a synthesis filterbank, and wherein the synthesis filterbank derives an output signal from the normalized high band signal.

32. A computer-readable medium configured to store a set of instructions executable to:

determine a normalization factor for a current frame of a signal, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal;

normalize the current frame of the signal based on the normalization factor that is determined; and

adjust the states'"'"' normalization factor based on the normalization factor that is determined.

33. The computer-readable medium of claim 32, wherein the non-linear values are squared values.

34. The computer-readable medium of claim 32, wherein the non-linear values are cubic values.

35. The computer-readable medium of claim 32, wherein the normalization factor is selected so that saturation does not occur.

36. The computer-readable medium of claim 32, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of a synthesis filter, and where the synthesis filter derives an output synthesized speech signal from the normalized low band excitation signal.

37. The computer-readable medium of claim 32, wherein the signal is a low band excitation signal, wherein the normalized signal is a normalized low band excitation signal, wherein the states are filter states of high-band excitation generator, and wherein the high-band excitation generator derives a high-band excitation signal from the normalized low band excitation signal.

38. The computer-readable medium of claim 32, wherein the signal is an input speech signal, wherein the normalized signal is a normalized input speech signal, wherein the states are filter states of an analysis filterbank, and wherein the analysis filterbank derives an output signal from the normalized input speech signal.

39. The computer-readable medium of claim 32, wherein the signal is a high band excitation signal, wherein the normalized signal is a normalized high band signal, wherein the states are filter states of a synthesis filterbank, and wherein the synthesis filterbank derives an output signal from the normalized high band signal.

40. An apparatus that is configured for dynamic normalization to reduce loss in precision for low-level signals, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being executable to;

determine a first gain of a first frame, wherein the first frame is a current frame;

determine a second gain of a second frame, wherein the second frame is a previous frame;

derive a number of bits corresponding to the first gain and the second gain; and

subtract the number of bits corresponding to the first gain and the second gain from a normalization factor associated with the first frame, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal.

41. The apparatus of claim 40, wherein the first gain and the second gain are a linear predictive coding (LPC) gain.

42. The apparatus of claim 40, wherein the apparatus is a handset.

43. The apparatus of claim 40, wherein the number of bits corresponding to the first gain and the second gain is derived using a mapping schema.

44. A method for dynamic normalization to reduce loss in precision for low-level signals, comprising:

determining a first gain of a first frame, wherein the first frame is a current frame;

determining a second gain of a second frame, wherein the second frame is a previous frame;

deriving a number of bits corresponding to the first gain and the second gain; and

subtracting the number of bits corresponding to the first gain and the second gain from a normalization factor associated with the first frame, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal.

45. The method of claim 44, wherein the first gain and the second gain are a linear predictive coding (LPC) gain.

46. The method of claim 44, wherein the method is implemented by a handset.

47. The method of claim 44, wherein the number of bits corresponding to the first gain and the second gain is derived using a mapping schema.

48. An apparatus that is configured for dynamic normalization to reduce loss in precision for low-level signals, comprising:

means for determining a first gain of a first frame, wherein the first frame is a current frame;

means for determining a second gain of a second frame, wherein the second frame is a previous frame;

means for deriving a number of bits corresponding to the first gain and the second gain; and

means for subtracting the number of bits corresponding to the first gain and the second gain from a normalization factor associated with the first frame, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal.

49. The apparatus of claim 48, wherein the first gain and the second gain are a linear predictive coding (LPC) gain.

50. The apparatus of claim 48, wherein the apparatus is a handset.

51. The apparatus of claim 48, wherein the number of bits corresponding to the first gain and the second gain is derived using a mapping schema.

52. A computer-readable medium configured to store a set of instructions executable to:

determine a first gain of a first frame, wherein the first frame is a current frame;

determine a second gain of a second frame, wherein the second frame is a previous frame;

derive a number of bits corresponding to the first gain and the second gain; and

subtract the number of bits corresponding to the first gain and the second gain from a normalization factor associated with the first frame, wherein the normalization factor depends on an amplitude of the current frame of the signal, and wherein the normalization factor also depends on non-linear values of states after one or more operations were performed on a previous frame of a normalized signal.

53. The computer-readable medium of claim 52, wherein the first gain and the second gain are a linear predictive coding (LPC) gain.

54. The computer-readable medium of claim 52, wherein the number of bits corresponding to the first gain and the second gain is derived using a mapping schema.