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标题: 关于重采样的问题，麻烦大神帮忙看看 [打印本页]

作者: loveeatmore 时间: 2019-8-15 15:02
标题: 关于重采样的问题，麻烦大神帮忙看看

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
2 ^* |2 T3 N4 ?+ D, U' V  ufa = 8000; %%signal frequency$ w% M0 z  B3 P7 Y
fs = 44100; %%44.1kHz sampling frequency
9 \2 u$ ~$ `1 Tn = 1:64;
0 J6 U+ x6 E$ D7 j: V* f" Zx = sin(2*pi*fa*n/fs);
  d, t6 q! N8 R$ w; r/ llengthx = length(x);
) T3 {; Q2 c' G% A+ Y$ Dt = n*1000/128/fs;
$ ^  M; z5 f8 O7 c%plot(t,x);xlabel('time in ms');

% [y fs nbits] = wavread('acoustic.wav');. t! u% }  X) U* a& B: Q; x
% x = y';& z1 O/ K6 k( V- ~' r7 `% i: s# I
% lx = length(x);4 p% R1 Q/ P) ?( x% S1 T
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
$ D  c) n8 @6 i%Resample parameters
. g% ^) K2 u/ y4 a$ KL1 = 8;; [( l/ J% E3 n' i! Q1 L2 X
M1 = 7;
" K- ]6 Y, l6 A; _0 B2 o( q: KL2 = 4;
. ]+ k0 Z; k1 |, aM2 = 3;1 x* `1 m4 x& [, m
L3 = 10;# M  M0 K' }9 N! H
M3 = 7;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
4 M3 Y9 e9 Z4 k6 H! d. R%%filters5 g: F* j& ?8 v$ k4 w8 J
load filter.mat& e. _+ s2 L. `4 h& N$ B. e
filter1 = b1; ( f$ r" y$ m! t$ D# V4 ]: W2 s
filter2 = b2;
9 ^/ ^- j8 i6 @7 Qfilter3 = b3;9 H- P0 N7 O, {+ c7 ~- o
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%2 i ~1 U2 o' A
%Initialize the subfilters

%First Filter0 A( g4 v7 O# K& }) x$ `8 W
upFilter1 = decompose(filter1,L1);- ^# ?2 ^! f% c1 c# y
downFilter1 = decompose(filter1,M1);

%Second Filter5 l6 ` y/ c2 l3 D4 i
upFilter2 = decompose(filter2,L2);
; m* S$ y! C, x! {3 \. p+ l- wdownFilter2 = decompose(filter2,M2);

%Second Filter; U& q* y# y" {8 |3 T) e
upFilter3 = decompose(filter3,L3);
1 Z% `, q8 A0 t: o5 ^downFilter3 = decompose(filter3,M3);

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

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
* J1 d c8 A1 Z0 S%Polyphase Filtering

%First Filter
; Q. i# Y8 G2 ~' K; v+ |7 }%! `) |9 v+ r- e2 r- T) J! z
%%upsampling
7 z* M; w! c, X+ ?# Yintermediatex1 = zeros(L1,length(x));
, M1 x& D& z* L8 h3 g6 B1 X0 \ cx11 = zeros(L1,length(x)*L1);% i* k# v/ r3 \9 k
for i = 117 c. j7 {6 ]& n4 M$ Y/ W
intermediatex1(i, = filter(upFilter1(i,,1,x); %%do the filtering before upsampling
3 V5 L6 B' P* B: X9 ^+ Ix11(i, = upsample(intermediatex1(i,:),L1); %%upsample by L, inserting L-1 zeros.
' }6 e7 u2 \# ?0 y6 e5 z2 rend

X1 = zeros(1,length(x)*L1);0 ^; N& S% g- D# b8 ~/ f1 d
for i = 1:length(x)9 `9 Y/ b& }+ y4 @0 |
X1(L1*(i-1)+11*(i-1)+L1) = x11(:,(i-1)*L1+1)';
" a2 ^6 a7 l8 [4 w5 @end
# S& P/ Q' {1 T0 L%%downsampling
. H& h2 @/ C, eX1_down = [X1 zeros(1,M1-mod(length(X1),M1))];! v6 m' Q  s; F1 X7 K
output1 = zeros(1,length(X1_down)/M1);- m% f) \7 `6 e6 o" ^7 ~9 b
x1down = zeros(M1,length(X1_down)/M1);
. w1 H+ N/ M9 E. Qx11down = x1down;
% b* f4 e5 T4 `* q! W2 ~. vfor i = 1:M1
' ]3 w# Q4 S/ r$ gfor k = 1:length(X1_down)/M1
$ a' F; Z$ p* u( d1 l  Tx1down(i,k) = X1_down(M1*(k-1)+i);" W: O: N* D1 R$ b
end! Y/ @9 J) ^0 i  c
x11down(i,:) = filter(downFilter1(1,:),1,x1down(i,:));$ d' Q' ^4 \- a  ~9 |" I
output1 = output1 + x11down(i,:);
- P: r' x0 m8 G, ]% Dend

%Second Filter
8 z1 N# x1 j* {" N3 B%
' u, C/ y) {/ A%%upsampling- \5 |3 n! M4 K& E2 E* {
intermediatex2 = zeros(L2,length(output1));7 L$ a& b8 X2 h4 X, ]6 S/ R
x22 = zeros(L2,length(output1)*L2);
: k6 C8 z* G1 u2 F5 \& qfor i = 12
2 F5 T# V2 c, k+ t+ ^' I' Tintermediatex2(i,:) = filter(upFilter2(i,:),1,output1); %%do the filtering before upsampling/ y& f& f1 X, y
x22(i,:) = upsample(intermediatex2(i,:),L2); %%upsample by L, inserting L-1 zeros.
- Y6 Z0 v+ c+ h9 B0 G# Aend

X2 = zeros(1,length(output1)*L2);
5 p! u  Z1 k+ J( _9 Bfor i = 1:length(output1)
0 `+ C# x8 y, @( [( f. m% D- yX2(L2*(i-1)+1:L2*(i-1)+L2) = x22(:,(i-1)*L2+1)';# u$ v6 s- P9 |1 c0 P
end
! h9 ?, R- s) E  G: j  s5 v%%downsampling! e# E- ]4 n2 I
X2_down = [X2 zeros(1,M2-mod(length(X2),M2))];
) X8 x& z" j1 v( V" voutput2 = zeros(1,length(X2_down)/M2);- C. v, v2 c5 ]1 d/ F1 f( V/ _, c
x2down = zeros(M2,length(X2_down)/M2);* z0 F8 e, X( E+ x6 R9 Q! K" K
x22down = x2down;+ a1 s; u% r1 a9 w* ]* X
for i = 1:M2
  l" [, C* |+ i) x3 t9 K9 [8 C' a' sfor k = 1:length(X2_down)/M20 F$ `" x: ~6 c1 g) r: l$ R
x2down(i,k) = X2_down(M2*(k-1)+i);7 s6 N" s! a! _3 ]
end
& {# F) B- P& k& ^" D3 w) G$ m  zx22down(i,:) = filter(downFilter2(1,:),1,x2down(i,:));
4 {$ a7 k0 O. R& goutput2 = output2 + x22down(i,:);9 K3 |3 B+ o/ @5 c; K) G5 ]
end

%Third Filter
( o8 x& W% \, c2 n" j% K%# D5 b, Y- `, t; o8 M0 h/ m
%%upsampling, J) j- |: }! e$ r* c" I
intermediatex3 = zeros(L3,length(output2));% B7 |" h% D M9 @
x33 = zeros(L3,length(output2)*L3);
, m) A4 D( G8 W/ C4 o3 J* |for i = 1:L3
r& D, c4 j, eintermediatex3(i,:) = filter(upFilter3(i,:),1,output2); %%do the filtering before upsampling
5 z0 p% H7 k. i4 ox33(i,:) = upsample(intermediatex3(i,:),L3); %%upsample by L, inserting L-1 zeros., f/ m. g6 x# ]9 c" j
end

X3 = zeros(1,length(output2)*L3);( k7 c3 S; x+ z$ H5 F# u
for i = 1:length(output2)
! `/ Q' t; I2 K( {/ l3 UX3(L3*(i-1)+1:L3*(i-1)+L3) = x33(:,(i-1)*L3+1)';
' t4 Y1 x! t1 S, Fend
  g% J3 \0 Z- x7 i%%downsampling/ a" l' a) m) U! l4 k) X* ?
X3_down = [X3 zeros(1,M3-mod(length(X3),M3))];: a' y  r: }* H: B
output3 = zeros(1,length(X3_down)/M3);
: Z& _* _+ S, c. ~4 B! \) T: m% vx3down = zeros(M3,length(X3_down)/M3);( M, b7 E& ~! ~2 Z! ]/ W3 f
x33down = x3down;
" G; G  m2 v% r& N; d" z. k+ Wfor i = 1:M3
2 y% e+ E. w) i: C; `for k = 1:length(X3_down)/M3
) i. @' W, ~' s& ox3down(i,k) = X3_down(M3*(k-1)+i);, k- y) X2 P0 n8 b* N- u) c
end3 v2 t) M1 G8 ~' [9 n/ R
x33down(i,:) = filter(downFilter3(1,:),1,x3down(i,:));
+ }$ p7 ^* g9 m/ x+ Zoutput3 = output3 + x33down(i,:);$ m8 g/ A( d" E6 V+ N
end

output3 = output3/max(output3);
( z! o* \# N& x7 W4 R' clout = length(output3);

nx = 1:length(output3);2 X1 Y2 w- o* V
xorigin = sin(2*pi*fa*nx/96000);7 \( U m9 P+ t& _& l4 l
error1 = xorigin - output3;
& {: \5 U" a# G. t& |0 J: Xyin = [0 0 resample(x,320,147)];
' o0 ~$ C/ i4 V" herror2 = xorigin - yin;

figure(1)7 z1 H# s1 i. {* S
subplot(3,1,1);plot(xorigin);title('True Signal');. w/ g: X! ?0 F
subplot(3,1,2);plot(output3);title('Resampled Signal');+ r8 [4 n5 v- F: u8 v; v
subplot(3,1,3);plot(error1);title('Error');

figure(2)
; \0 k% u$ d% ?" wsubplot(3,1,1);plot(xorigin);title('True Signal');
8 ^( H" k. W" S* A9 c: \9 o2 lsubplot(3,1,2);plot(yin);title('Built-in Resampled Signal');
, T" }* }- y6 _2 i1 m. ]+ {/ Dsubplot(3,1,3);plot(error2);title('Error');

function x_decompose = decompose(x,factor)
c; w4 `( v+ @' _8 \lx = length(x);

if mod(lx,factor) ~= 0;
j+ \% X8 \( B! o* X' N2 ?4 _X = [x zeros(1,factor-mod(lx,factor))];* v9 q6 O( w3 P8 d, ?
else/ }, N; R; v1 N" z9 \; V
X = x;
( ?( M6 e) ]$ u, v. X0 _" zend

x_decompose = zeros(factor,length(X)/factor);5 ?) X! w1 A7 ^4 A% P
for i = 1:factor
7 e# I9 H) x5 L, T r2 N+ V9 Afor k = 1:length(X)/factor, j& @0 N- g2 z8 ^' e
x_decompose(i,k) = X(factor*(k-1)+i);
" R# ~. I! x# J& W" {; hend v) X( E1 ]$ Z/ B8 W5 A
end

end

%Filter Generation
/ j9 e0 f6 j0 Q5 K! A: p8 s6 Jfs = 44100;( d8 c0 c4 {! V
L1 = 8;$ i7 b7 r) _5 n3 b+ G/ Z- u
M1 = 7;
0 H! K% L& I4 fL2 = 4;6 r4 S5 M4 B( L
M2 = 3;
: G0 o3 @* _6 }( _7 eL3 = 10;3 _# A* T& F0 a# r% O
M3 = 7;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
5 D, E" `- y  n. \5 [% h8 |3 [1 G' X%
0 v5 N# r6 C8 T) `1 C%%First Filter+ D! y- O$ m/ `2 r: h0 ~2 u# y: g6 N
f1 = [20000 24000];
+ y: E' T9 N& s& Z( D. pa1 = [1 0];
/ U- y& ?: W- E: R  g8 q. _dev1 = [0.01 10^-8];7 N& t+ W9 x' \$ K+ i2 ?, [
fs1 = fs*L1;
2 ~2 r& ~  a+ q: f[n1 fo1 ao1 w1] = firpmord(f1,a1,dev1,fs1);7 z, u1 a+ Z- N$ u
b1 = firpm(n1,fo1,ao1,w1);

%%Second Filter
% Y( u+ h7 }& E4 H1 O6 \+ p. y- uf2 = [20160 30240];
/ \! ^+ ?+ {- m6 {a2 = [1 0];2 h; l5 W9 Y7 f
dev2 = [0.01 10^-8];. n0 O3 L& I6 g5 I- ` O( h
fs2 = fs1*L2/M1;
1 L6 d$ `2 H0 i, d# {[n2 fo2 ao2 w2] = firpmord(f2,a2,dev2,fs2);
9 }7 U* g! ~* Ob2 = firpm(n2,fo2,ao2,w2);

%%Third Filter; D+ N) r5 q0 |' |" m0 l
f3 = [16800 50400];
, d# w* o& n5 R( Z4 z2 ra3 = [1 0];
8 M' I3 s$ a: A: [& m* x Kdev3 = [0.01 10^-8];7 x1 g4 s; G0 b5 S4 O8 a" c
fs3 = fs2*L3/M2;7 M& J( Y$ z J+ n4 j+ h! x7 U
[n3 fo3 ao3 w3] = firpmord(f3,a3,dev3,fs3);
3 l6 C/ W( h4 n* C' Zb3 = firpm(n3,fo3,ao3,w3);

作者: 木棉花_MM 时间: 2019-8-15 18:32
这个……

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