Log Area Ratios
Encyclopedia
Log area ratios can be used to represent reflection coefficient
s (another form for linear prediction coefficients
) for transmission over a channel. While not as efficient as line spectral pairs
(LSPs), log area ratios are much simpler to compute. Let
be the kth reflection coefficient of a filter, the kth LAR is:
Use of Log Area Ratios have now been mostly replaced by Line Spectral Pairs, but older codecs, such as GSM-FR use LARs.
Reflection coefficient
The reflection coefficient is used in physics and electrical engineering when wave propagation in a medium containing discontinuities is considered. A reflection coefficient describes either the amplitude or the intensity of a reflected wave relative to an incident wave...
s (another form for linear prediction coefficients
Linear predictive coding
Linear predictive coding is a tool used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive model...
) for transmission over a channel. While not as efficient as line spectral pairs
Line spectral pairs
Line spectral pairs or line spectral frequencies are used to represent linear prediction coefficients for transmission over a channel. LSPs have several properties that make them superior to direct quantization of LPCs...
(LSPs), log area ratios are much simpler to compute. Let
be the kth reflection coefficient of a filter, the kth LAR is:
Use of Log Area Ratios have now been mostly replaced by Line Spectral Pairs, but older codecs, such as GSM-FR use LARs.