针对暂态信号的时频分布特点,提出了采用小波包的去噪新方 法。首 先采用小波包变换对暂态信号进行多尺度分解,搜索子频带范数随尺度变化而增大并达到峰 值的子频带,然后对子频带内的小波系数进行阈值处理,最后进行信号重构。理论分析和实 验结果表明本方法简单、有效。
)!
|0>}_pE?@E2_p7.!"G
7"%$&#G
77%!"G#$%!"#&’(!)!#"G’7"%)&#G
7%!%#+"G$%*+#&’(
%
%
69’(>*%++$
-
pXxCTIHsTL=Rd]BF-rCO;yK2E}\Y9![1d}‘Ty8K7_pC[a
7,G
uk[s87_p2’PvK_}~{3:;k*=T_IRE}?FEM-#R
-%
N3b
ch
)m3:(!-$+%./0Chi0h%
)
-%$+-$+%.C
RIH=q2_p7CAI%fpC!*G
N3bch].{WK_e*2hi
N3b
ch
N3b
ch
N3b
ch
/#)1)%0*,.#/$+)1.%0%*%$/%+)1#)0%,++/.+)1,)0%%!+/!$)1"%0.$+.
/,)1)$0+!*+/$%)1.$0%#"$/%.)1#$0$*#+/.!)1,$0%""*/*")1"$0$!"%
/")1)$0),*+/$.)1.$0")",/%!)1#%0,%#)/#,)1,)0$%$)/$$))1"%0)%"!
/%%0.%!!)1)/.)0%,,$)1./!.0%#)")1#/$,%0$+"%)1,/)%$0*!*")1"
R.=/_pXxI7hj]}‘~2_p7!*GS.+*G
I%
e}Qv_pXxI
SIHhjJ(U]}‘~xE_p7CI62+*G
?gtHW}R2mO2@4w2C_}-,)--=q2_pAsG}‘@PRoiJ1,2$$!!34C@E}9!CHgzXhL7K^"^7.#"G+*G?,CGw<N3be2zXBhC#.#)w‘$kl<N3bchCAI)fpCF6N3bch]
I.E}~2_p!sT
r);N
m$n6789:&;<:(=2>:?@:&A8B:(’?C7D:@:A(2E4FGHIGJ&’?K:B:?&:(:B<:(
<?7LL@<:3M7A;:M7A<&(2G=NFO32$**%2
m%n_A}2NX{jYb!F1_p\Y62qg2FG.9/
&sK912$**!2
m)n6’?’;’6526:H?’<(<?P9Q(’KAHA;B:(;’@3<?PC=OOOC>B7?(2’?=?K2
I)
<?,w2N3bch
7)G.>;:’BQC$**#C!",$)w,%"2
m.nc6CZ+Z2HgNX{j?x>}_p28N(?C$**,C".
"!w!%2
m#nmBCCg;2/_NXR5Xl!6K28N(?C$***C#.
$*w%$R2
m,nRBK7?<3<(GS2=?AB’38&A<’?A’G<P?7@TB’&:((<?P2O?P@:C’’3E@<KK(CIS.
TB:?A<&:/7@@C$**,2
hiA-%5%QK_KQe*2’L.0N3bC
%+
fpR@9C_e/!/.+)%#v)%7,/)%#2che7Qj/.+1fe2}‘E?BQC_}-aBGv{)%,C
GltzXBhk+o*K/L;E.0N3bC
}‘E?Cy4BFAI.fpCJIHE}~2_
$%&’()*)’+,)’*-,’-,’%(.**)+’,/.*)’+0,1%/%-2,34%-5<?F<?
U;8V8’P8
71234564!"3"78$9(:$";9<9=>C?54=@297)$++).G
=?A;<(L7L:B7?:C?’<(:&7?&:@@<?PM’A;’38(<?PC7D:@:AL7&W:A<(LB’L’(:32N&&’B3<?PA’A;:A;:3<(AB<98H
A<’?’KA;:<?(A7?A7?:’8((<P?7@<?A<M:HKB:X8:?&Q(L7&:CA;:<?(A7?A7?:’8((<P?7@<(3:&’ML’(:3C<A;C7D:@:AL7&W:AAB7?(K’BM7A<’?7?3A;:(8997?3A;7A(8997?3H?’BMB:7&;:(L:7WD78@:C<A;(&7@:7B:(:7B&;:32>;:?A;:C7D:@:A&’:KK<H&<:?A(<?A;:(8997?37B:3:7AC<A;A;B:(;’@32J<?7@@QA;:(<P?7@<(B:&’?(AB8&A:324’A;A;:’B:A<&7@7?7@Q(<(7?3A;:B:(8@A(’K:YL:B<M:?A(<?3<&7A:A;7AA;<(M:A;’3<((<ML@:7?3B:@<79@:24;<=>8?6
C7D:@:AL7&W:AC<?(A7?A7?:’8((<P?7@(C(8997?3H?’BM
,56789:7