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% RLS 算法
8 J6 m q8 H- O+ k8 Z; D( c* t- c<br>randn('seed', 0) ;& {0 k+ E/ c, }4 P! d2 X
<br>rand('seed', 0) ;1 S5 n) y5 ^' y1 ?1 `( ?; Z6 i0 ]
<br>" J8 j& G; \) L4 l
<br>NoOfData = 8000 ; % Set no of data points used for training5 a: c }8 |7 S6 T" t
<br>Order = 32 ; % Set the adaptive filter order, `: B; Q6 o2 v+ P- ?
<br>9 ]4 C$ u1 h7 @+ S, e
<br>Lambda = 0.98 ; % Set the forgetting factor
# N* a% q0 L( W) l3 \$ O" _<br>Delta = 0.001 ; % R initialized to Delta*I5 F2 M3 u. I5 x9 Z" u( J) u
<br>
+ K4 ^2 t5 e( A* n3 b- [3 k3 w<br>x = randn(NoOfData, 1) ;% Input assumed to be white
9 E8 y9 ^/ ?5 m. c3 H. g' e<br>h = rand(Order, 1) ; % System picked randomly" [+ i' X! |: J
<br>d = filter(h, 1, x) ; % Generate output (desired signal)
- }, I$ K# c8 Q6 T1 j<br>
5 ^$ W! W- p0 i<br>% Initialize RLS
# P9 |2 r3 d' P- o& v8 J2 a0 N<br> D" L% u6 j" H; r9 t$ C C' U4 n
<br>P = Delta * eye ( Order, Order ) ; D/ ^: C6 ~* N0 Y* q
<br>w = zeros ( Order, 1 ) ;
9 p3 f7 h* l6 T8 E3 A<br>
' y8 \, w9 y8 c4 P<br>% RLS Adaptation; l& E) Z) }1 r* l$ X
<br>
/ e) N2 b2 x* j; z) j<br>for n = Order : NoOfData ;
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# f; p6 r! n0 l- f& q<br>u = x(n:-1:n-Order+1) ;
* H0 r5 _( s6 f9 h: z) u<br>pi_ = u' * P ;
) C( ?. @, |- |$ s E1 X' f- M# b<br>k = Lambda + pi_ * u ;% F+ B/ ~* O; [& F+ K" J9 I
<br>K = pi_'/k;( l4 }5 B3 {/ i# o9 a! [
<br>e(n) = d(n) - w' * u ;
" z2 N/ ?1 ] O* b8 x<br>w = w + K * e(n) ;) s9 E }8 t g7 P4 D. m. T" B
<br>PPrime = K * pi_ ;6 }% M2 ^( v0 m1 T
<br>P = ( P - PPrime ) / Lambda ;
+ h! c; t/ J; i! Y; W1 r- c# @/ ^1 x<br>w_err(n) = norm(h - w) ;
# b" R. w! E4 q4 r<br>
9 K F' b- r; V) B( g<br>end ;5 l) f% i& B9 M& N% v& n C
<br>/ o3 v( g7 ?7 H& }$ p5 o; e0 @
<br>% Plot results
% f6 F: J" g" t) w6 h- e<br>
3 V8 R1 K% k& f2 r* v& D( u. D<br>figure ;
6 c4 E( s# y( O7 e. `% g8 ?% g4 S<br>plot(20*log10(abs(e))) ;
" k) T# n& e. i: e: y+ y7 d1 N<br>title('Learning Curve') ;2 A; v! s( t9 W1 a0 P' [' E4 G
<br>xlabel('Iteration Number') ;4 O" g% Y. l0 Q0 H8 k# z. u3 @" |# [: S
<br>ylabel('Output Estimation Error in dB') ;# D# k+ c p7 o0 z7 U6 h* S; g9 X
<br>
# a- r0 g: n) K/ b<br>figure ;
, a2 k. w+ a& G! \* u( h* q( `3 I<br>semilogy(w_err) ;
- Y2 c4 u2 L1 F" @<br>title('Weight Estimation Error') ;& N# W5 H$ Y- T! D1 g* w# z" r
<br>xlabel('Iteration Number') ;) G3 h# B$ l& i; o" @4 L& e4 |
<br>ylabel('Weight Error in dB') ;
. s% c" ?/ j( R _) U<br>
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