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关于重采样的问题,麻烦大神帮忙看看

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发表于 2019-8-15 15:02 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式

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自己在matlab里面编的一个重采样程序,但是效果很差,而且输出前一段数据有错,麻烦路过的大神帮我看看?

%input data
4 u! M- a1 j) A7 kfa = 8000; %%signal frequency) ]% K$ |& J  P: J
fs = 44100; %%44.1kHz sampling frequency! v2 a( u, {3 Q4 _, Q( _
n = 1:64;
1 {) d1 o3 u' Cx = sin(2*pi*fa*n/fs);
1 N  v! [! F/ l- @% G2 q( S% olengthx = length(x);* ^7 [' ~* U! F4 ?1 J: Z  |
t = n*1000/128/fs;
9 i' I) X& I6 G& H* [- w%plot(t,x);xlabel('time in ms');

% [y fs nbits] = wavread('acoustic.wav');
4 }& ~' @" ^0 o6 u; `) N% x = y';
+ `/ E, a+ M( l5 \- g: l0 V3 I+ Q( D% lx = length(x);- l& \+ i# B. e5 w! ^' Y+ p
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
; N, X4 g& Z0 f: w7 b# J" \! _3 O: t( G%Resample parameters
- ]7 a6 u2 s2 N% |! ~L1 = 8;
' w7 J0 v: T6 U7 S, O% [M1 = 7;
! l( t: @  C) a& G& j" iL2 = 4;7 T; \+ B+ O9 x9 X5 C- |' m
M2 = 3;
& ^7 G- R2 i0 j- @L3 = 10;
0 e5 l; s# N2 G  uM3 = 7;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
* j' ^2 G  Q8 }9 z$ l3 l- _% P%%filters
# K6 s2 m1 e% r/ Z- M8 F/ Zload filter.mat' G5 V1 S. `, v' X3 t
filter1 = b1;
. D1 |, [+ X: x% d- a+ Pfilter2 = b2;* S. I9 b, J) V, S+ F5 v3 Q
filter3 = b3;# h" k* z2 \5 X) L, }! F( K
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5 z7 ^- i$ S2 m, E! J
%Initialize the subfilters

%First Filter
1 Y; u) {) ~5 q5 uupFilter1 = decompose(filter1,L1);
1 C' Q. V# n0 v  ^downFilter1 = decompose(filter1,M1);

%Second Filter2 l/ G, b; U2 m1 b8 w) T
upFilter2 = decompose(filter2,L2);
/ M( j; `; i6 }. ]: `/ {, QdownFilter2 = decompose(filter2,M2);

%Second Filter0 U& w) m. E1 ]* J& ^& F5 T9 @
upFilter3 = decompose(filter3,L3);9 e2 C2 |$ {! \0 z' D4 j
downFilter3 = decompose(filter3,M3);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
* D5 y$ b; n* P/ t! \  |%Polyphase Filtering

%First Filter
# t6 W6 h+ K% p2 h7 |% h9 \%
' p7 W* i0 j. n" h2 u$ e! ^3 d1 O%%upsampling6 x& a1 M8 h) w2 V2 t7 |
intermediatex1 = zeros(L1,length(x));$ e" Z1 H. `& {$ S
x11 = zeros(L1,length(x)*L1);
+ _1 G9 k4 m+ I' b% dfor i = 11
4 z! u8 S; N0 C* `: a6 ?! I) W4 H7 |intermediatex1(i, = filter(upFilter1(i,,1,x); %%do the filtering before upsampling  e9 g& Q' b4 y; I& l! f
x11(i, = upsample(intermediatex1(i,:),L1); %%upsample by L, inserting L-1 zeros.
2 h2 |! m1 H3 t, r+ i7 xend

X1 = zeros(1,length(x)*L1);6 F: ^* W7 V: F! D: d( J
for i = 1:length(x)) ?' s" |2 W4 X8 j; a0 j8 ]
X1(L1*(i-1)+11*(i-1)+L1) = x11(:,(i-1)*L1+1)';4 ~+ B6 P9 b" }9 J& v, J
end. \1 v' f8 x) `" L
%%downsampling
4 [% \- ?9 l4 p1 \X1_down = [X1 zeros(1,M1-mod(length(X1),M1))];
" U9 x6 k3 B4 routput1 = zeros(1,length(X1_down)/M1);
. p! D: U0 ?1 ^+ E! f5 ~x1down = zeros(M1,length(X1_down)/M1);1 n8 `  l" E  M
x11down = x1down;
9 F0 {2 h5 m2 l* W( W* P# Tfor i = 1:M1" w* S6 Q; Q7 i0 f" g. K
for k = 1:length(X1_down)/M1
' x! N# O. R3 p4 \9 kx1down(i,k) = X1_down(M1*(k-1)+i);
$ Z! i; o+ q3 K3 |% G8 rend
: g4 \, X; P7 G7 o$ e2 Yx11down(i,:) = filter(downFilter1(1,:),1,x1down(i,:));+ k4 E6 w6 J) U/ q3 b3 O- e0 d1 z
output1 = output1 + x11down(i,:);9 x$ M% k; Q. F! q+ G5 c
end

%Second Filter
5 C) L8 [, A. G6 b" y  g( x; Y7 }%
' w* G8 P! ]) `, ^5 N8 l1 A) e%%upsampling/ x. Q; |4 j" @+ D  A  B8 W7 Z
intermediatex2 = zeros(L2,length(output1));) C& ^3 s$ R' ^. \
x22 = zeros(L2,length(output1)*L2);
, B& O( b: @( J+ ]2 ]( ?+ }for i = 12* x4 A+ V0 z; G. B& M5 F/ @; ~
intermediatex2(i,:) = filter(upFilter2(i,:),1,output1); %%do the filtering before upsampling) @% l* n7 G/ y6 S
x22(i,:) = upsample(intermediatex2(i,:),L2); %%upsample by L, inserting L-1 zeros.3 |8 G' G* I4 f( o' f+ X/ x2 I
end

X2 = zeros(1,length(output1)*L2);
+ T0 [9 v6 }6 g% Q" x2 F9 _for i = 1:length(output1)
, Y% ?0 S& r6 `: \. nX2(L2*(i-1)+1:L2*(i-1)+L2) = x22(:,(i-1)*L2+1)';
) S- B9 {$ }, m7 ^8 b. t- Nend* ~0 k7 O$ i2 p8 t5 b2 d) o$ K
%%downsampling  l9 [+ \, \/ F7 @! r" M
X2_down = [X2 zeros(1,M2-mod(length(X2),M2))];
  c. g0 v+ u& \output2 = zeros(1,length(X2_down)/M2);% P+ Z6 l4 r& `. O6 Y( C/ L
x2down = zeros(M2,length(X2_down)/M2);- w* |3 Q% b7 ?" v' a
x22down = x2down;
7 _/ k7 g2 `) w' `7 Tfor i = 1:M29 G' b2 m, p- h' v
for k = 1:length(X2_down)/M2
5 q% l, L0 J* y/ P" t& Ix2down(i,k) = X2_down(M2*(k-1)+i);
# I& A; I1 y( j1 ~0 send
$ D1 w; D! Z! L1 M! {/ x- zx22down(i,:) = filter(downFilter2(1,:),1,x2down(i,:));
4 [5 J& W% G, b1 B& routput2 = output2 + x22down(i,:);. Z. r# k- h+ o; |+ i, e
end

%Third Filter
4 ?/ k7 `* p! u# a5 i7 C%
) _# b6 H  J, T& Z1 c%%upsampling
* G. O  y+ v; |& g6 L+ f' |9 f% l: Vintermediatex3 = zeros(L3,length(output2));$ ?3 N# H+ ]+ V8 E  G
x33 = zeros(L3,length(output2)*L3);, D& d3 B$ w) p8 I' k5 ^
for i = 1:L37 W5 E$ ~5 K$ y' o# ^2 I
intermediatex3(i,:) = filter(upFilter3(i,:),1,output2); %%do the filtering before upsampling
- R4 z7 ~  f1 g- v( P- f6 @# Zx33(i,:) = upsample(intermediatex3(i,:),L3); %%upsample by L, inserting L-1 zeros.1 \1 v& f8 l9 @2 _# a0 Q
end

X3 = zeros(1,length(output2)*L3);5 n- f  o2 m+ X2 o7 S
for i = 1:length(output2)8 b' Z) L4 X4 I5 v, ^* ]* @
X3(L3*(i-1)+1:L3*(i-1)+L3) = x33(:,(i-1)*L3+1)';
" H5 f) t9 Q4 T" U7 B1 R+ d$ b' N7 hend0 M6 |, {% I- x# [) i
%%downsampling  {2 ~; x& D/ ?: z6 m, ~$ [
X3_down = [X3 zeros(1,M3-mod(length(X3),M3))];5 k$ I3 ^1 W9 Q% J. U6 M
output3 = zeros(1,length(X3_down)/M3);% r3 y- p. O1 `1 K! U# d5 e$ Y  [
x3down = zeros(M3,length(X3_down)/M3);. s: E  d8 x+ A" Z  y" }
x33down = x3down;
2 ^& h' G: z5 hfor i = 1:M3
0 [$ J; H" c8 r3 ^for k = 1:length(X3_down)/M30 O' i/ f7 s& M/ J& A% p
x3down(i,k) = X3_down(M3*(k-1)+i);3 g7 _: l; f, r5 j( n
end
+ W0 k' ]2 K- S, `$ ?) sx33down(i,:) = filter(downFilter3(1,:),1,x3down(i,:));. E( {" u; F$ [
output3 = output3 + x33down(i,:);
% {0 t" _; p" y& q# K+ U6 h+ [end

output3 = output3/max(output3);3 w* S8 l8 W# f+ c, }
lout = length(output3);

nx = 1:length(output3);6 ^) V( K6 Q' j
xorigin = sin(2*pi*fa*nx/96000);
' V4 b5 d3 W, {" u+ X% P% z4 Ferror1 = xorigin - output3;; {6 N4 S( |: T  u4 ?( y  k
yin = [0 0 resample(x,320,147)];; y, [6 b5 [) ]. {6 E' r& e
error2 = xorigin - yin;

figure(1), S; V+ f8 K2 l$ T" a! ?
subplot(3,1,1);plot(xorigin);title('True Signal');
6 [# }. @& ]0 \0 r  ~- ysubplot(3,1,2);plot(output3);title('Resampled Signal');# H5 u0 J* y, z' v8 M
subplot(3,1,3);plot(error1);title('Error');

figure(2)5 x0 q  r- N, H
subplot(3,1,1);plot(xorigin);title('True Signal');0 A  |5 |! q4 @) ^& o2 z* c5 ]( A* A
subplot(3,1,2);plot(yin);title('Built-in Resampled Signal');, {; j2 b, ~( M* p" J: C
subplot(3,1,3);plot(error2);title('Error');


function x_decompose = decompose(x,factor)
' y9 P- U+ |; q; L- U, O1 ulx = length(x);

if mod(lx,factor) ~= 0;+ X' k# `# b) z3 n
X = [x zeros(1,factor-mod(lx,factor))];
; ]* u6 k/ R, Q6 Selse+ |4 [/ C, [/ Y1 a5 n
X = x;
- r7 l2 ~  a* u" G/ h# j) bend

x_decompose = zeros(factor,length(X)/factor);
) ~# M+ m5 F" ?* G9 Afor i = 1:factor
+ l: J( h; A8 L/ O( Tfor k = 1:length(X)/factor9 ~) {9 M: U2 n$ e: e
x_decompose(i,k) = X(factor*(k-1)+i);
7 ^, K- I, T0 nend
/ U$ o$ @: ?# n0 ]; bend

end

%Filter Generation( W4 n" X2 L, C$ ]
fs = 44100;
- g1 w" V9 x/ D4 wL1 = 8;
& j; u+ X9 G- O3 j- oM1 = 7;! h; p& l# p/ m: H1 @
L2 = 4;8 k& s4 P' ], |- R3 {0 L& `/ n
M2 = 3;
# f8 m% G+ j: Q& ^L3 = 10;1 g, Q5 g9 ^+ ^8 L) n- t. b
M3 = 7;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
" @2 q0 ?1 U$ A+ ?  x%( _; {3 x- d5 w4 V
%%First Filter8 n0 D$ Q2 ?7 `1 m, d; t
f1 = [20000 24000];/ f; n3 x; ^. D/ C. `& m
a1 = [1 0];
0 a- M/ R, Q  O4 e  f2 kdev1 = [0.01 10^-8];$ N# |8 i7 r, n, y
fs1 = fs*L1;
) X7 Q  g0 R: C+ M5 X[n1 fo1 ao1 w1] = firpmord(f1,a1,dev1,fs1);
2 D, l/ f* ~" |. sb1 = firpm(n1,fo1,ao1,w1);

%%Second Filter
( E1 x0 v3 G( _+ ~" g$ g3 Qf2 = [20160 30240];  `& D) ^7 V0 q' X' {+ s
a2 = [1 0];
4 L7 p& b6 c9 F$ U: t' \dev2 = [0.01 10^-8];
7 i" s, b" H& q2 q) P4 Sfs2 = fs1*L2/M1;
* ^6 Q" B1 v/ Y; A) R[n2 fo2 ao2 w2] = firpmord(f2,a2,dev2,fs2);3 v- B6 j3 M5 B; q, Z- Y  ?3 y
b2 = firpm(n2,fo2,ao2,w2);

%%Third Filter- O9 H- n. \  W% {
f3 = [16800 50400];
' {3 @3 Q) K9 Z2 b( s0 @a3 = [1 0];# S: w$ c0 J0 R
dev3 = [0.01 10^-8];" D) Q! r: w" Z+ H) a% B$ O
fs3 = fs2*L3/M2;
+ z. t4 P1 m+ J; c[n3 fo3 ao3 w3] = firpmord(f3,a3,dev3,fs3);
  I; ]9 O, _; o4 F2 Ob3 = firpm(n3,fo3,ao3,w3);


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