Linear predictive coding(LPC) is defined as a digital method for encoding an analog signal in which a particular value is predicted by a linear function of the past values of the signal.
Human speech is produced in the vocal tract which can be approximated as a variable diameter tube. The linear predictive coding (LPC) model is based on a mathematical approximation of the vocal tract represented by this tube of a varying diameter. At a particular time, t, the speech sample s(t) is represented as a linear sum of the p previous samples.
The LPC is the linear predictive filter which allows the value of the next sample to be determined by a linear combination of previous samples.
LPC is frequently used for transmitting spectral envelope information, and as
such it has to be tolerant of transmission errors. Transmission of the filter
coefficients directly (see linear prediction for
definition of coefficients) is undesirable, since they are very sensitive to
errors. In other words, a very small error can distort the whole spectrum, or
worse, a small error might make the prediction filter unstable.
LPC is generally used for speech analysis and resynthesis. LPC synthesis can be used to construct vocoders where musical
instruments are used as excitation signal to the time-varying filter estimated
from a singer's speech.
(This is compilation on LPC)
To view .ppt on this topic visit http://www.slideshare.net/sdd2311/lpc-29316427
References:
[1] "Linear Predictive Coding" by Jeremy Bradbury, December 2000.
[2] www.ieee.com
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