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Ti liu tham khoLa parole et son traitement automatique Calliope, Masson, 1989 Traitement de la parole Rene Boite et Murat Kunt, Presse Polytechnique Romandes, 1987 Fundamentals of Speech Signal Processing Saito S., Nakata K. , Academic Press, 1985 Digital Processing of Speech Signals Lawrence R. Rabiner, Ronald W. Schafer, Prentice-Hall .1978 PrenticeDiscrete-Time Processing of Speech Signals DiscreteJohn R. Deller, John G. Proakis, Hansen John H. L. 1999 Ting Vit hin i (Ng m, ng php, phong cch) Ti Vi hi (Ng ng ph c Nguyn Hu Qunh, H Ni, 1994 Nguy H Qu H Dn lun Ngn ng hc lu ng Nguyn Thin Gip, on Thin Thut , Nguyn Minh Thuyt, H Ni, 1994 Nguy Thi Gi o Thi Thu Nguy Thuy H1
X L TING NITrnh Vn Loan Tr B mn K thut My tnh K thu M t Khoa CNTT, HBK H Ni H
http://dce.hut.edu.vn
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Ni dung1. Mt s khi nim c bn M s kh ni b 2. X l tn hiu ting ni X t hi ti n 3. M ho ting ni ho ti n 4. Tng hp ting ni T h ti n 5. Nhn dng ting ni Nh d ti n
1. Mt s khi nim c bnX l thng tin cha trong tn hiu ting ni ch t hi ti n nhm truyn, lu tr tn hiu ny hoc tng nh truy tr hi n ho t hp, nhn dng ting ni. nh d ti n Cc nghin cu c tin hnh x l c ti h ting ni yu cu nhng hiu bit trn nhiu ti n c nh hi bi nhi lnh vc ngy cng a dng: t ng m v v ng c d t ng v ngn ng hc cho n x l tn hiu... ng x t hi3 4
1
Mc chM ho mt cch c hiu qu tn hiu ho c c hi qu hi ting ni truyn v lu tr ting ni. ti n truy v tr ti n Tng hp v nhn dng ting ni tin h nh d ti n ti ti giao tip ngi-my bng ting ni. ti ng b ti n Tt c cc ng dng ca x l ting c d c x ti ni u cn phi da trn cc kt qu c ph d c k qu ca phn tch ting ni t ti n5
Mt s khi nim c bnPhn bit ting ni v m thanh bi ti n v Ting ni c phn bit vi cc m Ti n bi v c thanh khc bi cc c tnh m hc c kh b c t h c ngun gc t c ch to ting ni. ngu g t ch ti n C 2 loi ngun m lo ngu tun hon (dy thanh rung) tu ho tp m (dy thanh khng rung)6
B my pht m
B my pht m
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8
2
B my pht m
S khi b my pht m
NASAL CAVITY: Khoang mi SOFT PALATE: Vm ming mm EPIGLOTTIS: Np thanh qun VOCAL FOLDS (CORDS): Dy thanh OESOPHAGUS: Thc qun TRACHEA: Kh qun PHARYNX: Hng
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1. Mt s khi nim c bn s kh ni c
Thanh mn
Thanh mn cc v tr ht, th,pht m, ni th tho v tr th ,ph n th th
Thanh mn Dy thanh
A. Glotte pendant la respiration B. Glotte pour la phonation 1. Glotte 2. Cordes vocales 3. Epiglotte 5. Cartilages arytnodes11 12
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Dy thanh trong mt chu k dao ng
Biu din tn hiu ting niDng sng theo thi gian s th
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File WAVTn s ly mu: 8kHz, F1= 11025 Hz, s m 2F1, 4F1 (16kHz, 10kHz) S bit/mu: 8,16 bit/m Mono, Stereo
Biu din tn hiu ting niPh tn hiu ting ni Ph hi ti n
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16
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Biu din tn hiu ting niSpectrogram (Sonagram)
Biu din tn hiu ting ni
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Biu din tn hiu ting ni
Biu din tn hiu ting niThu bng micro khc loi b kh lo
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Biu din tn hiu ting niHai ging khc nhau cho cng mt m gi kh c m
Biu din tn hiu ting niCng ngi ni, cng mt m ng n c m
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Nng lng, t l bin thin qua gi tr khng l t bi gi trfile:C:\wav\1-6-5-8-10-0.wav, ss,es:1, 43029, window length, shift (samples):160, 40, wtype:1 0.4 amplitude 0.2 0 -0.2 -0.4 -0.6 0 short-time energy 4 3 2 1 0.5 short-time magnitude 15 10 5 0.5 80 60 40 20 0 0.5 1 1.5 2 time in seconds 2.5 3 3.5 1 1.5 2 2.5 3 3.5 ZC 1 1.5 Mn 2 2.5 3 3.5 0.5 1
To m hu thanh Formant v antiformant3.5
Signal 1.5 En 2 2.5 3
zero crossing rate
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To m v thanh
Mt s c im ng m ting Vitn m tit ti C thanh iu (6), bin i thanh iu i bi i km theo bin i ngha bi ngh Khng bin i hnh thi bi h th
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26
Mt s c im ng m ting VitH thng m v: 14 nguyn m (11 th v nguyn m n, 3 nguyn m i, 22 ph m) n, i, ph1 2 3 4 5 6 7 8 9 10 11 i,y e a o u ch ch ch ch e d d a ha mt b ph ph n cn c t t t co ro l m27
Mt s c im ng m ting VitH thng m v: 22 ph m th v ph1 2 3 4 5 6 7 la tha, tha, lt l 8 9 10 11 b p v ph m t th d,gi n l bng bnh b p p vn v phi pha m mng m t ai tin tng t th thn th duyn, gi gi nng long lanh 12 13 14 15 16 17 18 19 20 21 22 tr s r ch nh ng,ngh c,k,q kh g,gh h x trng tr sinh vin rng chng nhc nh ng ngh con,kt,qua con,k khc kh g gh gh h h xa xi28
1
ia,y,ya,i (c ia, y) ua,u (c ua) a, a, (c a) a)
kia ka, yu k kiu, khuya, tin ki tin ti tua rua, lun
2 3
7
Mt s c im ng m ting VitPhn loi nguyn m theo nng lo ca li v chuyn ng ca li l v chuy c l nng Hng trc tr gia gi sau u i cao e o trung bnh b e a thp th
Mt s c im ng m ting VitPhn loi nguyn m theo m ca lo ming v chuyn ng ca li mi v chuy c lHng m hp hi hp h hi rng r rng ihng trc tr ia,y,ya,i hng sau khng trn mi hng sau trn mi
a
a
u ua o
e
29
30
Mt s c im ng m ting VitPhn loi ph m theo tc hay xt, lo ph t x hu thanh hay v thanh, mi ha h mV tr cu m Phng thc cu m Bt hi V thanh Tc n Khng bt hi Hu thanh Vang mi V thanh Hu thanh Vang bn p Mi u li Rng th t tr ch c,k,qu Vm ming Mt li Cui li Hng
Mt s c im ng m ting Vitm tc: ting n, pht sinh do lung kh t phi i ra b cn tr hon t ti n ph lu kh ph b tr ho ton, phi ph v s cn tr thot ra. to ph ph tr tho m xt: ting c xt, pht sinh do lung khng kh i ra b cn tr x ti c ph lu kh b tr khng hon ton (ch b kh khn), phi lch qua mt khe h nh v ho to (ch kh khn), ph l m h nh trong khi thot ra nh vy phi c xt vo thnh ca b my pht tho v ph c v th c b ph m. Ph m bn: u li tip xc vi li chn li thot ca khng kh, Ph bn: l ti x v l ch l tho c kh buc n phi lch qua khe h hai bn cnh li tip gip vi m bu n ph l h c l ti gi v m m ra ngoi to nn ting xt nh (l). ngo t ti x nh Lung khng kh thot ra ngoi b cn tr, to nn ting xt hay ting Lu kh tho ngo b tr t ti x ti n, dng tn hiu khng tun hon gi l ting ng (n). d t hi tu ho g l ti ( Trong khi pht m mt s ph m, dy thanh cng hot ng ng ph m s ph c ho thi to nn ting thanh. th t ti Ph m c t l ting ng ln hn gi l ph m n. Ph c ti l g l ph Ph m c t l ting thanh ln hn gi l ph m vang. Ph c ti l g l ph
b m ph v
n x d,gi l nh s r ng,ngh kh g31
Xt
n
h
32
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Dng sng mt s t ting Vit
Dng sng mt s t ting Vit
ph
b
tr
tm
v
ch
tm33
nh34
Dng sng mt s t ting Vit
Dng sng mt s t ting VitCHUR.WAV, Fs = 11025Hz, 5669 samples, Time = 514ms 0.5
0.4
0.3
0.2
Amplitude
k
0.1
l
0
-0.1
-0.2
-0.3
-0.4
-0.5 0 50 100 150 200
kh
250 Time in ms
300
350
400
450
500
35
36
9
Dng sng mt s t ting Vit0.4 DDEER.WAV, Fs = 11025Hz, 5278 samples, Time = 479ms 0.3
Dng sng mt s t ting VitKHAR.WAV, Fs = 11025Hz, 7718 samples, Time = 700ms 0.4
0.2
0.2
0.10
Amplitude
0
Amplitude
-0.2
-0.1-0.4
-0.2
-0.3
-0.6
-0.4 0 50 100 150 200 250 Time in ms 300 350 400 450
-0.8
0
100
200
300 Time in ms
400
500
600
37
38
Dng sng mt s t ting VitN G H IR .W A V , F s 0 .3 = 1 1 0 2 5 H z , 6 7 0 7 s a m p le s , T im e = 6 0 8 m s
Dng sng mt s t ting VitXOA.WAV, Fs = 11025Hz, 7690 samples, Time = 697ms 0.6
0.40 .2
0 .1
0.2
Amplitude
0
-0 .1
Amplitude0 1 0 0 2 0 0 30 0 T im e in m s 4 0 0 5 0 0 6 0 0
0
-0.2
-0 .2
-0.4-0 .3
-0.6
-0.8
39
0
100
200
300 Time in ms
400
500
600
40
10
Dng sng mt s t ting VitP H A I R . W A V , F s = 1 1 0 2 5 H z , 6 9 3 4 s a m p le s , T im e = 6 2 9 m s 0.6
Dng sng mt s t ting VitMEJ.WAV, Fs = 11025Hz, 4922 samples, Time = 446ms 0.2
0.150.4
0.10.2
0.05Amplitude 0
Amplitude0 100 200 300 T im e in m s 400 500 600
0
-0 . 2
-0.05
-0 . 4
-0.1
-0 . 6
-0.15
41
-0.2 0 50 100 150 200 250 Time in ms 300 350 400
42
Dng sng mt s t ting VitBUF.WAV, Fs = 11025Hz, 6779 samples, Time = 615ms 0.6
Dng sng mt s t ting VitTAMS.WAV, Fs = 11025Hz, 4989 samples, Time = 452ms 0.4
0.3
0.40.2
0.1
0.20
Amplitude
Amplitude
-0.1
0
-0.2
-0.2
-0.3
-0.4
-0.4
-0.5
-0.6
-0.6 0 100 200 300 Time in ms 400 500 600
43
0
50
100
150
200 Time in ms
250
300
350
400
450
44
11
Dng sng mt s t ting VitGIAF.WAV, Fs = 11025Hz, 8772 samples, Time = 796ms 0.4
Dng sng mt s t ting VitVIF.WAV, Fs = 11025Hz, 9872 samples, Time = 895ms 0.3
0.30.2
0.2
0.1
0.1
0 AmplitudeAmplitude 0
-0.1
-0.2-0.1
-0.3
-0.4
-0.2
-0.5
450 100 200 300 400 Time in ms 500 600 700
-0.3 0 100 200 300 400 500 Time in ms 600 700 800
46
Dng sng mt s t ting VitKHOONG.WAV, Fs = 11025Hz, 6743 samples, Time = 612ms 0.4
Dng sng mt s t ting VitNHAAN.WAV, Fs = 11025Hz, 5713 samples, Time = 518ms
0.6
0.20.4
0 AmplitudeAmplitude
0.2
-0.2
0
-0.4
-0.2
-0.6
-0.4
470 100 200 300 Time in ms 400 500 600
0
50
100
150
200
250 Time in ms
300
350
400
450
500
48
12
Dng sng mt s t ting VitLAJ.WAV, Fs = 11025Hz, 5442 samples, Time = 494ms
Dng sng mt s t ting VitTRIJ.WAV, Fs = 11025Hz, 4108 samples, Time = 373ms 0.4
0.40.3
0.2
0.2
Amplitude
Amplitude
0
0.1
0
-0.2-0.1
-0.4-0.2
-0.6
-0.3
0
50
100
150
200
250 Time in ms
300
350
400
450
49
0
50
100
150
200 Time in ms
250
300
350
50
Dng sng mt s t ting VitSOOS.WAV, Fs = 11025Hz, 8888 samples, Time = 806ms 0.4
Dng sng mt s t ting VitTIMF.WAV, Fs = 11025Hz, 5589 samples, Time = 507ms 0.6
0.3
0.40.2
0.1
0.2 Amplitude
Amplitude
0
0
-0.1
-0.2
-0.2-0.3
-0.4
-0.4
-0.5 0 100 200 300 400 Time in ms 500 600 700 800
510 50 100 150 200 250 Time in ms 300 350 400 450 500
52
13
M hnh to ting ni (Fant-1960)u(n)T0
M hnh ton im cc (AR)Ti bc x Tib x bc x R(z) R(z)
Lc thng Lc thng thp G(z) thp G(z)
Tuyn m Tuy m Tuyn V(z) V(z)
T( z ) = G ( z )V ( z )R ( z ) =x(n)
A( z )
G(z ) =
A (1 + z 1 )(1 + z 1 )V(z ) = BK
R ( z ) = C(1 z 1 )
A(z): Hm truyn t ca b lc o H truy c b T( z ) = A( z )A(z) = 1 +p2K +1 i =1
azi
i
A(z) = a i z ii =0
p
a0 = 1
(1 + b1k z 1 + b 2k z 2 )k =153
x( n ) + a i x ( n i ) = u ( n )i =1
P = 2K+154
M hnh ARMA1 2 C( z ) + = T( z ) = A1 ( z ) A 2 ( z ) A( z )
Di thngBin C( z ) = c i z -ii=0 q
c0 = 1
1 1/ 2 Di thng Bk
x( n ) + a i x( n i ) = c i u ( n i )i =1 i =0
p
q
Fk55
Tn s
56
14
2. X l tn hiu ting niPhn tch ph t phB lc hiu chnh Ca s Hamming FFT Log |.|
x(n)
N
B lc hiu chnh H(z) = 1 az-1, a = 0,95..0,98 hi ch57
frame
0
58
X l ng hnh (homomorphic)s(n)=h(n)*e(n) S() = H().E() S( H( ).E( log[S()]= log[H()]+ log[E()] log[S( log[H( log[E( F-1{log[S()]} = F-1{log[H()]} + F-1{log[E()]} {log[S( {log[H( {log[E( -1{log[S()]} = $ F {log[S( s(n) $ F-1{log[H()]} = h(n) {log[H( -1{log[H()]} = $ F {log[H( e(n)
S khi x l ng hnh
B lc hiu chnh
Ca s Hamming
FFT
Log |.|
FFT-1
$ $ $ s(n) = h(n) + e(n)59
$ s(n)60
15
V dc(n)T0 T0
Tin on tuyn tnh (Linear Prediction Coding)M hnh AR hTin on o Sai s tin on s o Sai s bnh phng ton phn s to ph Ti thiu ha sai s thi h s61
x(n) + ai x(n i) = u(n)i=1
p
$ $ x(n) = ai x(n i)i=1
p
$ e(n) = x(n) x(n)E = e2 (n)n
) h(n)
E $ ai
= 0, i = 1,2,...,p62
Xc nh tn s c bnGi tr F0 ph thuc vo gii tnh v Gi tr ph thu v gi t v la tui tu Ging nam: 80..250 Hz Gi Ging n: 150..500 Hz Gi nTinTn hiu ting ni
Mt s phng php xc nh FoDa vo hm t tng quan v h t Da vo hm vi sai bin trung bnh v h b Dng b lc o v hm t tng b v t quan X l ng hnh h
Xc nh Fo
nh gi kt qu
x l
63
64
16
Da vo hm t tng quanTnh hm t tng quan R(k) ca tn hiu ting ni h t t hi ti n x(n) N 1 k
Phng php t tng quan c ci tinHn ch, loi b |x| < CL ch lo b
R(k ) =
n =0 Fs = 10 kHz, N = 300, K = 150.Tm cc i trong khong (0, K) 150.T c kho
x(n) x(n + k ) k = 0,1,..., K
65
66
Da vo hm vi sai bin trung bnh (Average Magnitude Difference Function)D (k ) = x(n + m) x(n + m k ) k = 0,1,..., Km=02 D(iP) = 0, i = 0,1,... N u (n) N u (n) n=0 n=0
V d0.3 0.3 0.2 0.2 0.1 0.1 0 0 -0.1 -0.1 -0.2 -0.2 700 700 0.015 0.015 0.01 0.01 0.005 0.005 0 0 -0.005 -0.005 -0.01 0 -0.01 0.2 0.2 0.15 0.15 D(k) D(k) 0.1 0.1 750 750 800 800 850 850 900 900 950 n 950 n 1000 1000 1050 1050 1100 1100 1150 1150
N 1
1
1 N-1 D(k ) = [ x(n + m) x(n + m k )]2 N m=0 1/ 2 1 k = 0,1,..., K = [2r (0) 2r (k )] N vi < 167
1/2
r(k) r(k)
x(n) x(n)
N 1
1
N 1
1/ 2
0
50 50
100 100
150 k 150 k
200 200
250 250
300 300
0.05 0.05 0 0 0 50 50 100 100 150 k 150 k 200 200 250 250 300 300
0
68
17
Dng b lc o (Simplified InverseFilter Tracking)10kHz
X l ng hnh
Thng thp th 4700Hz
Thng thp 900Hz
1-z-1
W(n) W(n)
LPC(p=4) LPC(p=4)
A(z)
Hm t tng quan
HT/VTnh gi kt qu Ni suy Tm cc i
Fo69 70
Xc nh formantTham s cn xc nh s x Formant Fk Di thng Bk
X l ng hnhTn hiu ting ni
B lc hiu chnh
Ca s
FFT
Phng php ph X l ng hnh h LPCLog10|.| FFT-1 FFT
Wc(n)71 72
18
X l ng hnh
Phng php LPCB lc hiu chnh
Ca s
Tnh h s ai Tm cc i Quyt nh
s(n)Tnh1/ |A(ej)| bng FFT
Fk,Bk
Tnh nghim ca A(z)73 74
3. M ha ting niDy thao tc m ho v gii m t ho giNhiu, suy gim, sai s
Mt s tnh cht thng k ca tn hiu ting niMt xc sut su N : s lng mu x(n) l mc bin trong khong [-/2, +/2] kho [ /2, /2]
Lc1 Lc1Nhiu, suy gim, sai s
AD AD
M ho M ho
Gii m Gii m
DA DA
Lc2 Lc2
n [-N,...,N] ,...,N x egodic v dng v
px ( ) = lim [ N /(2 N + 1)]N 075 76
19
Gi tr trung bnh v phng saiGi tr trung bnh ca tn hiu dng Gi tr b c t hi d N 1 x = px ( ) d = lim N x(n) N 2 N + 1 n = vi tn hiu ting ni x = 0 t hi ti n Phng sai
Lng t tc thi (khng nh)Lut lng t y = Q(x) c nh ngha: Lu l t Q(x) ngh (L+1) mc tn hiu x(0), x(1), ..., x(L) m t hi L mc lng t ho m l t ho
x2 =
2 px ( ) d = lim
N 1 N x 2 (n) N 2 N + 1 n =77
Mi mc lng t ho biu din bng t b bit m l t ho bi di b t L = 2b. Sai s lng t (tp m lng t) e = Q(x) - x s l t (t l t Bc lng t : hiu 2 mc tn hiu k nhau B l t hi m t hi k (i) = x(i)-x(i-1) x(i)-x(iThng lng I = bFs (bit/s). Fs : tn s ly mu l t s m
78
Thng lngTn hiu lng t 8 bit (256 mc), Fs = 8 hi l t m kHz Thng lng = 64 kbit/s l Tn hiu lng t 16 bit (65536 mc), hi l t m Fs = 16 kHz Thng lng = 256 kbit/s , l 1 gi ting ni ~100 Mbyte gi ti n ~100 Cn phi m ho tn hiu ting ni (MPEG, ph ho hi ti n GSM, G723, ...) truyn ting ni trn mng ti n truy m hoc lu tr ho tr79
Thng lngTn s ly s mu (kHz) 48 44,1 32 22 8 S bit cho 1 mu m 16 16 16 12 8 Thng lung kbit/s lu 768 705,6 512 264 64 Dung lng / l pht (kbyte) ph 11520 10584 7680 3960 960 Lnh vc v Ghi m chuyn nghip nghi CD Audio Radio FM Radio AM in thoi i tho80
20
Lng t uTng qut, bc lng t l hm ca bin tn qu b l t c hiu x (lng t khng u) n gin nht l hi (l t gi nh l lng t u. l t Mc lng t c chn gia 2 mc tn hiu l t ch gi m t hi y(i) = (1/2)[x(i-1)+x(i)] (1/2)[x(iLut lng t u v i xng c trng bi: Lu l t v x b cc mc bo ho xs m ho mc lng t L hoc (L+1) = 2b. l t ho Bc lng t = 2xs/L B l t
Lng t uL=9
81
82
Lng t u1 1
Lng t uL = 161 1 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2
0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0 00
-0.2 -0.2 -0.4 -0.4 -0.6 -0.6 -0.8 -0.8 -1 -1 0
0
-0.2 -0.2 -0.4 -0.4 -0.6 -0.6 -0.8 -0.8
0
2
2
4
4
6
6
8
8
10 10
12 12
14 14
-1 -1 0
0
2
2
4
4
6
6
8
8
10 10
12 12
14 14
83
84
21
Lng t u1 0 1 0
Cc tnh cht lng t uMt xc sut sai s lng t su s l t l pe ( ) = p x (i + ), l = ( L 1) / 2i = l
-1 -1 0 0 1 1 0 0
2
2
4
4
6
6
8
8
10 10
12 12
-1 -1 0 0 1 1 0 0
2
2
4
4
6
6
8
8
10 10
12 12
phn b u gia - /2 v + /2 b gi v pe ( ) = 1/ , / 2 = 0, > / 2 Trung bnh tp m /lng t = 0 b t l t 2 2 Phng sai e = 2 / d = 2 /1285
-1 -1 0 0 0.2 0.2 0 0
2
2
4
4
6 Quantific ation E rror 6 Quantific ation E rror
8
8
10 10
12 12
-0.2 -0.2 0
0
2
2
4
4
6
6
8
8
10 10
12 12
/ 2
86
Cc tnh cht lng t uT s tn hiu trn nhiu hi nhi xs SN = 10 lg (d B) = 6, 02b + 4, 77 20 lg x 2 x 2 e
T s tn hiu trn nhiuSN = Nng lng tn hiu Ws = Nng lng nhiu Wn
SN dB = 10 log 10 SNhoc ho
Nu xs = 4 max SN (d B) = 6b 7,3Vi b 6, tng 6 dB mi khi tng 1 bit lng t. bit l t c cht lng thch hp cn c b 11 ch l th h c c87
SN dB = 20 log 10
Bi n tn hiu Bi n nhiu88
22
T s tn hiu trn nhiuNng lng l Tn hiu = Nhiu hi Nhi Tn hiu = 2 Nhiu hi Nhi Tn hiu = 10 Nhiu hi Nhi Tn hiu = 100 Nhiu hi Nhi Tn hiu = 1000 Nhiu hi Nhi Tn hiu = 10N Nhiu hi Nhi SN (dB) 0 2 10 20 30 N x 1089
Lng t logaritSau khi ly logarit bin tn hiu s m ho tuyn l ) hi s ho tuy y(n) tnh y(n) x(n) log[] log[] signe[] signe[] y'(n) x'(n) x'(n)
Q[] Q[]
M ha M ha
c(n)
c(n)
Gii m Gii m
exp[] exp[]
signe[x(n)]90
Lng t logaritHai gii php dng cho in thoi gi ph d i tho Lut (dng M) Lu (d
Lng t logaritHai gii php dng cho in thoi gi ph d i tho Lut A(dng chu u) Lu A(d u)1 + log A x 1 + log AA = 87,56
y =
log(1 + x ) log(1 + )
y =
= 255
8 bit logarit ~ 12 bit lng t u bit bit l t 91 92
23
Lng t thch nghiBc lng t tu thuc vo bin tn hiu B l t tu thu v hi Thch nghi trc Th tr y(n)= x(n) G(n) x(n) y(n)
Lng t thch nghi Thch nghi sau Thx(n) c(n) y(n) Q[] Q[] y(n)
M ha M ha
Q[] Q[]
M ha M ha
c(n)
Thch nghi Thch nghi k.i k.i
G(n)
G(n)
G(n)
y'(n)
Thch nghi Thch nghi k.i k.i Gii m Gii m Thch nghi Thch nghi k.i k.i c(n)
y'(n) x'(n) = G'(n)
:
y'(n)
Gii m Gii m
c(n) G(n)93
y'(n) x'(n) = G'(n)G(n)
:
94
Mt s chun m ho m thanh/ting niG.721 : ADPCM, 32 kbps, 4bits, 8kHz ADPCM, 4bits, 8kHz G.722 : ~ADPCM, 48 n 64 kbps, ~ADPCM, G.723 : ~ADPCM, 24 kbps, 3 bits, 8kHz ~ADPCM, kbps, 8kHz G.728 : 16 Kbps 16 Kbps GSM : in thoi di ng, 13 kbps i tho Linear Predictive Encoding (Xerox), 5 kbps Code Excited Linear Prediction (CELP) Digital Video Interactive : ~ADPCM, 4 n 8 bits ~ADPCM, VoIP: G723.1 (6.4kbits/s), G728, G729 (8kbits/s)95
4. Tng hp ting niTo ting ni xut pht t biu din ti n xu ph t bi di ng m ca li ni ng c l n K thut tng hp ting ni: thu t h ti n Tng hp trc tip h tr ti Tng hp da trn m hnh h d hB tng hp formant h B tng hp dng LPC h d B tng hp m phng b my pht m h ph b ph96
24
Phn loiCht lng b tng hp: Mc t nhin Ch l b h M Mc r Thanh iu i Ng iu Ng i
Tng hp trc tipGhi m ting ni t nhin ti n t - n v ghi m v - Ghp cc n v ghi m: t, cu. Gh c v t n v ghi m v 97
S lng t vng: l t Hn ch ch Khng hn ch h ch
B tng hp ting ni t vn bn (Text-toh ti n t b (Text- toSpeech)
m v v m tit (diphone) ti t t hp t t cu98
Tng hp formantF0 A1 To xung To xung A2 Khoang ming mi A3 Knh mi Knhm mi A4 To tp m Tot m tp
Tng hp LPCF1 F2 F3F0 To xung To xung A
B lc s B lc s s bc p bc pTo tp m Tot m tp a1 a2 ... ap
B1
B2 B399
Synthesis-by-Analysis100
25
M phng b my pht mNgun m Ngu Tuyn m Tuy
M hnh ngun m
Tham s iu khin s i khi
M phng ngun m (ngun tun hon) ph ngu (ngu tu hoM phng dy thanh:M hnh mt khi, M hnh ph h m kh h hai khi, M hnh nhiu khi, M hnh hai dm... kh h nhi kh h d
M hnh 2 khi
M hnh nhiu khi101
M hnh 2 dm
102
M phng tuyn m
M hnh phn xGi thit Gi thiRi rc ha
Vch ngn cng c Sng truyn n hng (dc theo trc truy h (d tr ng)ch xt cc tn s < 5000 Hz, bin t s ng)ch c bi thin din tch khng qu t ngt t ng di qu B qua tn hao: tnh lng, truyn nhit t t l truy nhi
103
104
26
ng tit din u, khng tn haong tit din u v ti di v ng dy tng ng
Tng t m hc in hcm hc h p: p sut su u: Thng lng lv(l,t)=0
in hc i h v: in p i i: Dng in i L: in cm i c C: in dung i
0/A: in cm m hc i c h A/0c2: in dung m hc A/ i h
H phng trnh Webster trx x u p u ( x, t) = u + t u t + = 0 c c x A t u A p x x c = p ( x, t ) = u + t + u t + 0 x 0 c 2 t c c A u: thng lng, p: p sut, : mt khng kh, c: vn tc sng m thng l su m kh v t s105
106
Xt trong min tn sSng ti v sng phn x c dng t v ph xj(t ) j ( t + ) x x c c u+ t = K +e , u t + = K e c c x x
p ng tn su ( l , t ) = U ( l , ) e j t 1 x = l U ( l, ) = U G ( ) cos ( l / c ) 1 p ng tn s H () = U (l, ) = t s U G () cos(l / c)
Ti mi
iu kin bin ti thanh mn i ki t
u (0, t ) = uG (t ) = U G ()e jt iu kin bin ti mi p (l, t ) = 0 i ki tp(x, t) = jZ0 sin[(l x)/ c] cos[(l x)/ c] UG ()e jt , u(x, t) = UG ()e jt cos l / c cos l / c
Z 0 ( ) = j
0A
107
H () vi (2n + 1)c f = 4l l = 17,5 cm, c=350 m/s f = 500,1500, 2500... Hz
108
27
M hnh phn x khng tn hao (Kelly-Lochbaum)+ + u k + 1 (t) u k + 1 (t - k + 1 ) + u k (t) + u k (t - k )
M hnh phn x khng tn hao (Kelly-Lochbaum)Tnh lin tc ca p sut v thng lng t c su v lp k (l, t) = p k +1 (0, t) u k (l, t) = u k +1 (0, t) 2 A k+1 A Ak + u k+1 (t) = u + (t - ) + k+1 u k +1 (t) k A k+1 + A k A k+1 + A k A Ak + 2 Ak u (t+ ) = k+1 u k (t - ) + u +1 (t) k k A k+1 + A k A k+1 + A k
u k (t)
u k (t + k ) u k + 1 (t) u k + 1 (t + k + 1 )
0
lktit din Ak0
l k +1tit din Ak+1
Cc ng c bn c cng chiu di k = k +1 = b c chi d
l = c109
t h s phn x h ph x
rk =
A k+1 A k A k+1 + A k
u + (t) = (1 + rk ) u + (t - ) + rk u k +1 (t) k+1 k + u k (t+ ) = rk u k (t - ) + (1 rk ) u +1 (t) k
110
Phn b sngu+ (t) k
Hiu ng ca cc tn haotr + uk+1(t )
tr
u+ (t ) (1+ rk ) u+ (t) k+1 k
Tn hao do dch chuyn khng kh trong tuyn m d chuy kh tuy Do tnh lng ca khng kh t l c kh Do truyn nhit truy nhi Do rung vch ngn vtnh lng
rk
rk
uk (t)
tr ng k
u (t +) k
(1 rk ) uk+1(t)
tr ng k+1
uk+1(t+)
0
lTip gip
0
l
truyn nhit111
rung
112
28
Hiu ng ca cc tn haoTn hao do bc x ti mi b x M hnh qu bng v hn h qu h
Hiu ng chung ca cc tn haoDi thng
Bc x ti mi
Tr khng bc x Tr kh b x
Zr =
j Lr Rr p () = U (, l) Rr + j Lr
RungNhit+lng
128 8a Rr = 2 , Lr = 3 c 9 a: bn knh m ti mi113 114
5. Nhn dng ting niHai giai on: hun luyn (hc) nhn dng o hu luy (h nh d Phn loi theo lo S lng t vng l t T ri rc lin tc r t Mt ngi ni nhiu ngi ni ng n nhi ng n Nhn dng t cu Nh d t
Phn loi theo phc tpNhn dng t ring l, t vng t (
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