Prior art

To identify the most relevant prior art for US patent 6795805, I will access the USPTO Patent Public Search tool. Since the patent is expired, I will search for the patent number and then examine its cited references.

Upon reviewing US patent 6795805, the following patent citations are listed as prior art:

U.S. Patent Documents:

• U.S. Pat. No. 5,444,816

  • Full Citation: U.S. Patent 5,444,816 to Adoul et al., titled "Code excited linear prediction coding for speech with an algebraic codebook".
  • Publication/Filing Date: Issued on August 22, 1995. The priority date for US6795805 is October 27, 1998.
  • Brief Description: This patent describes a Code Excited Linear Prediction (CELP) coding system for speech, particularly focusing on the use of an algebraic codebook for determining the innovative excitation. The innovative codebook search in US6795805's preferred embodiment is stated to be performed using an algebraic codebook as described in this patent.
  • Potential Anticipated Claim(s): This patent potentially anticipates aspects of the innovative codebook used in US6795805, particularly its role in generating the innovative codevector, which is a component of claims 1, 11, and 21. Specifically, the concept of an innovative codebook (218) producing an innovative codevector (c_k) responsive to an index (k) is directly relevant to the methods and devices described in claims 1, 11, and 21.

• U.S. Pat. No. 5,699,482

  • Full Citation: U.S. Patent 5,699,482 to Adoul et al., titled "Code excited linear prediction coding with improved vector quantization".
  • Publication/Filing Date: Granted on December 17, 1997. The priority date for US6795805 is October 27, 1998.
  • Brief Description: This patent details improvements in vector quantization within CELP coding. Similar to U.S. Pat. No. 5,444,816, US6795805 references this patent in the context of the innovative codebook.
  • Potential Anticipated Claim(s): Like U.S. Pat. No. 5,444,816, this patent potentially anticipates aspects of the innovative codebook and its function in generating innovative codevectors, as described in claims 1, 11, and 21 of US6795805.

• U.S. Pat. No. 5,754,976

  • Full Citation: U.S. Patent 5,754,976 to Adoul et al., titled "Code excited linear prediction speech coder using adaptive post-filtering".
  • Publication/Filing Date: Granted on May 19, 1998. The priority date for US6795805 is October 27, 1998.
  • Brief Description: This patent addresses CELP speech coders with adaptive post-filtering. It is also cited by US6795805 as a reference for the innovative codebook.
  • Potential Anticipated Claim(s): This patent also likely anticipates aspects related to the innovative codebook and the generation of innovative codevectors as found in claims 1, 11, and 21 of US6795805.

• U.S. Pat. No. 5,701,392

  • Full Citation: U.S. Patent 5,701,392 to Adoul et al., titled "Code excited linear prediction speech coder using enhanced spectral matching".
  • Publication/Filing Date: Dated December 23, 1997. The priority date for US6795805 is October 27, 1998.
  • Brief Description: This patent focuses on CELP speech coders with enhanced spectral matching. It is another reference for the innovative codebook in US6795805.
  • Potential Anticipated Claim(s): This patent similarly anticipates elements concerning the innovative codebook and the production of innovative codevectors, relevant to claims 1, 11, and 21 of US6795805.