Method and apparatus for reconstructing a linear prediction filter excitation signal

• US 6,304,843 B1
• Filed: 01/05/1999
• Issued: 10/16/2001
• Est. Priority Date: 01/05/1999
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Choi, Hung-Bun, Wong, Harvey Hau-Fai, Wong, Wing Tak Kenneth
• Primary Examiner(s): Korzuch, William
• Assistant Examiner(s): Chawan, Vijay B
• Application Number:
  US09/226,914
• Time in Patent Office: 1,015 Days
• Field of Search: 704/219, 704/216, 704/217, 704/205, 704/218, 704/220, 704/258, 704/263, 704/262, 704/264, 704/268, 704/206, 704/208
• US Class Current: 704/219
• CPC Class Codes: G10L 19/08 Determination or coding of the excitation function; Determination or coding of the long-term prediction parameters

Abstract

An apparatus and method of reconstructing a linear prediction synthesis filter excitation signal, by: receiving a signal representative of output from a linear prediction synthesis filter, producing therefrom a deterministic signal comprising a magnitude spectrum (50) and a phase spectrum (52); and producing (54) the reconstructed excitation signal from the deterministic signal and a noise signal.

Claims

1. An apparatus for reconstructing a linear prediction synthesis filter excitation signal, the apparatus comprising:

means for receiving parameters representative of a signal'"'"'s magnitude and phase spectrum, and for producing therefrom a deterministic signal comprising a magnitude spectrum and a phase spectrum; and

means for receiving the deterministic signal and a noise signal and for reconstructing therefrom the linear prediction synthesis filter excitation signal,

wherein the phase spectrum is derived substantially from the formula;

2. An apparatus as claimed in claim 1 wherein the magnitude spectrum is substantially flat.

3. An apparatus as claimed in claim 1 wherein the value of γ

is substantially equal to |−

A(1)/A(0)|, where A(i) is the i^th autocorrelation function of the impulse response of the linear prediction synthesis filter.

4. An apparatus as claimed in claim 1 wherein the values of α

, β and

γ

are substantially equal.

5. An apparatus as claimed in claim 1 wherein the value of α

is substantially equal to unity.

6. A method for reconstructing a linear prediction synthesis filter excitation signal, the method comprising the steps of:

receiving parameters representative of a signal'"'"'s magnitude and phase spectrum, and producing therefrom a deterministic signal including a magnitude spectrum and a phase spectrum; and

receiving the deterministic signal and a noise signal and reconstructing therefrom the linear prediction synthesis filter excitation signal, wherein the phase spectrum is derived substantially from the formula;