1mlib_SignalLPCAutoCorrelGetmEendeiragLyi_bFm3Ll2ii(bb3r_MaSLriIygBn)FaulnLcPtCiAountsoCorrelGetEnergy_F32(3MLIB)
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6 mlib_SignalLPCAutoCorrelGetEnergy_F32 - return the energy of the input
7 signal
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10 cc [ flag... ] file... -lmlib [ library... ]
11 #include <mlib.h>
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13 mlib_status mlib_SignalLPCAutoCorrelGetEnergy_F32(
14 mlib_f32 *engery, void *state);
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18 The mlib_SignalLPCAutoCorrelGetEnergy_F32() function returns the energy
19 of the input signal.
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22 In linear predictive coding (LPC) model, each speech sample is repre‐
23 sented as a linear combination of the past M samples.
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25 M
26 s(n) = SUM a(i) * s(n-i) + G * u(n)
27 i=1
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31 where s(*) is the speech signal, u(*) is the excitation signal, and G
32 is the gain constants, M is the order of the linear prediction filter.
33 Given s(*), the goal is to find a set of coefficient a(*) that mini‐
34 mizes the prediction error e(*).
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36 M
37 e(n) = s(n) - SUM a(i) * s(n-i)
38 i=1
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42 In autocorrelation method, the coefficients can be obtained by solving
43 following set of linear equations.
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46 SUM a(i) * r(|i-k|) = r(k), k=1,...,M
47 i=1
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51 where
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53 N-k-1
54 r(k) = SUM s(j) * s(j+k)
55 j=0
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59 are the autocorrelation coefficients of s(*), N is the length of the
60 input speech vector. r(0) is the energy of the speech signal.
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63 Note that the autocorrelation matrix R is a Toeplitz matrix (symmetric
64 with all diagonal elements equal), and the equations can be solved
65 efficiently with Levinson-Durbin algorithm.
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68 See Fundamentals of Speech Recognition by Lawrence Rabiner and Biing-
69 Hwang Juang, Prentice Hall, 1993.
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72 The function takes the following arguments:
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74 energy The energy of the input signal.
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77 state Pointer to the internal state structure.
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81 The function returns MLIB_SUCCESS if successful. Otherwise it returns
82 MLIB_FAILURE.
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85 See attributes(5) for descriptions of the following attributes:
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90 ┌─────────────────────────────┬─────────────────────────────┐
91 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
92 ├─────────────────────────────┼─────────────────────────────┤
93 │Interface Stability │Committed │
94 ├─────────────────────────────┼─────────────────────────────┤
95 │MT-Level │MT-Safe │
96 └─────────────────────────────┴─────────────────────────────┘
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99 mlib_SignalLPCAutoCorrelInit_F32(3MLIB), mlib_SignalLPCAutoCor‐
100 rel_F32(3MLIB), mlib_SignalLPCAutoCorrelGetPARCOR_F32(3MLIB), mlib_Sig‐
101 nalLPCAutoCorrelFree_F32(3MLIB), attributes(5)
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105SunOS 5.11 2mlMiabr_S2i0g0n7alLPCAutoCorrelGetEnergy_F32(3MLIB)