Log area ratios (LAR) can be used to represent reflection coefficients (another form for linear prediction coefficients)[1] for transmission over a channel.[2] While not as efficient as line spectral pairs (LSPs), log area ratios are much simpler to compute. Let r_k be the kth reflection coefficient of a filter, the kth LAR is:[3]

A_k = \log{1-r_k \over 1+r_k}

Use of Log Area Ratios have now been mostly replaced by Line Spectral Pairs, but older codecs, such as GSM-FR use LARs.

See also

References

  1. ^ Chow, David & Abdulla, Waleed (January 2004). Speaker Identification Based on Log Area Ratio and Gaussian Mixture Models in Narrow-Band Speech: Speech Understanding / Interaction.. Vol. 3157. Lecture Notes in Computer Science. pp. 901–908. doi:10.1007/978-3-540-28633-2_95. ISBN 978-3-540-22817-2. – via ResearchGate
  2. ^ Strube, H. (October 1977). "Synthesis part of a "Log area ratio" vocoder in analog hardware". IEEE Transactions on Acoustics, Speech, and Signal Processing. 25 (5): 387–391. doi:10.1109/TASSP.1977.1162984. ISSN 0096-3518
  3. ^ Gutierrez-Osuna, Ricardo. "L7: Linear prediction of speech". Introduction to Speech Processing | Ricardo Gutierrez-Osuna | CSE@TAMU. p. 24.