?clc;
?close?all;
?clear?all;
?load（‘InputData.mat‘）;
?
?x?=?InputData;
?
?%?let?us?see?it;
?plot（x）;
?%?let?us?save?it
?fs_in?=??2.285714e+03?;
?WAVEFILE?=?‘input.wav‘;
?wavwrite（xfs_inWAVEFILE）;
?fs_out=?8000;
?%?let?us?listen?it
?sound（xfs_in）;
?
?%?output?and?input?ratio?is
?disp（[‘Sameprate?Convert?Ratio?is?‘num2str（fs_out/fs_in）]）;
?
?%3.5?=7/2
?disp（‘find?a?couple?of?relatively?prime?numbers?7/2?=3.5‘）;
?U=7;D=2;
?
?fprintf（‘Upsample?ratio?is?%d\n‘U）;
?fprintf（‘Downsample?ratio?is?%d\n‘D）;
?
?%Part?A
?%?transition?band?=?0.157080;過渡帶?（Transition-band?=?pi/20）
?%?pass?band?attenuation?<=?7.000000?dB?
?%?stop?band?attenuation?>=?40.000000?dB?
?%?comparing?Anti-alias?filter?and?Anti?mirror?filter
?%?Wc?=?min（pi/7pi/2）Wc?=?pi/7
?%?用海明窗函數(shù)設(shè)計(jì)低通濾波器
?wc?=?pi/7;
?ws=wc+pi/40;
?wp=wc-pi/40;
?
?%Part?B
?deltaw=?ws?-?wp;????????%?過渡帶寬Δω的計(jì)算
?N?=?ceil（6.6*pi/?deltaw）?+?1;????%?按海明窗計(jì)算所需的濾波器階數(shù)N0
?wdham?=?（hamming（N+1））‘;????????%?海明窗計(jì)算
?Wn=wc/（pi）??????;?????????????%?計(jì)算截止頻率這里要用歸一化的，否則fir1函數(shù)不認(rèn)
?b=fir1（NWnwdham）;
?[Hw]=freqz（b11024）;
?db=20*log10（abs（H））;
?%?畫頻響曲線
?figure
?fs_scaled?=1;
?plot（w*fs_scaleddb）;title（‘幅度響應(yīng)（單位：?dB）‘）;grid
?figure
?fs_scaled?=1;
?plot（w*fs_scaleddb）;title（‘幅度響應(yīng)（單位：?dB）‘）;grid
?axis（[0?pi?-45?5]）;?xlabel（‘歸一化頻率‘）;?ylabel（‘分貝‘）;
?set（gca‘XTickMode‘‘manual‘‘XTick‘[0pi]）;
?set（gca‘YTickMode‘‘manual‘‘YTick‘[-455]）;

?%系統(tǒng)能承受1024點(diǎn)fft，可以認(rèn)為把濾波器設(shè)置為這么長的長度
?delta_w=?pi/1024;????????????????????????????%搜索;濾波器是1024個(gè)點(diǎn)，對應(yīng)著pid的位置，對應(yīng)著fs/2的位置
?Ap=-（min（db（1:1:wp/delta_w+1）））?;??%實(shí)際通帶紋波
?As=-round（max（db（ws/delta_w+1:1:513）））??;??%實(shí)際阻帶紋波
?
?fprintf（‘Actuall?pass?attenuation?%f?dB?required?<=7dB\n‘Ap）;
?fprintf（‘Actuall?stop?attenuation?%f??dB?required?>=40dB\n‘As）;
?
%???Part?C
%?請清參考附圖

%??Part?D?
%??首先進(jìn)行7倍的插值
?U=7;
??
?Norignal=length（x）;
?%??Norignal=1024;
?x=x（1:Norignal）;?%截取前N個(gè)點(diǎn)計(jì)算不全算的話可以取前1024個(gè)點(diǎn)
?x1=zeros（1U*length（x））;???
?x1（1:U:end）=x;???%對信號進(jìn)行L倍直接插值
?
N?=?length（x1）;
%多相分解?134?階濾波器?134?=?67?*?2
for?r=1:67??%每相67個(gè)點(diǎn)
????for?k=1:2??%2倍抽取
????????hh（kr）=b（（r-1）*2+k）;
????end
end
%各路信號時(shí)延
for?k=1:2
????for?m=1:N-2
????????xk（km）=x1（m+k-1）;??%信號進(jìn)入各相經(jīng)過不同的延時(shí)
????end
end
%對時(shí)延后的信號2倍抽取
for?k=1:2
????for?m=1:2:N-2
????????xd（k（m-1）/2+1）=xk（km）;
????end
end
%多相濾波
n2=N/2-1;??%抽取后信號的點(diǎn)數(shù)
for?k=1:2
????for?m=1:n2
????????xdk（m）=xd（km）;
????end
????for?m=1:67
????????hhk（m）=hh（km）;
????end
????y=conv（hhkxdk）;n3=n2+67-1;??%卷積之后信號的點(diǎn)數(shù)=N/2-1+14-1=212
????for?m=1:n3
????????y1（km）=y（m）;
????end
end
yt=y1（1:）+y1（2:）??;%合并兩相

%?直接做卷積的結(jié)果
%?7倍抽取之后直接送入LPF
x2??=?conv（bx1）;
%?再對x2做兩倍的抽取得到x3
for?r=1:length（x2）/2??
????x3（r）?=?x2（（r-1）*2+1）;
end
%?x3就是直接濾波結(jié)果，把兩者作比較：
figure
plot（[100:200]yt（100:200）‘b‘）;
hold?on
plot（[100:200]x3（100:200）‘r‘）;
title（‘Output?comparasion?by?2?ways‘）;
legend（‘polyphase‘‘conventional‘）;
%?output?the?last?wave?files?at?8k?samperate
wavwrite（3.5*x3fs_out‘output1.wav‘）;
w

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----

?????文件?????906966??2014-12-13?11:53??PolyphaseFilter\block?diagram?for?a?polyphase?decomposition.bmp

?????文件??????14335??2014-12-13?15:40??PolyphaseFilter\Design.JPG

?????文件???????2977??2014-12-11?09:40??PolyphaseFilter\Email.txt

?????文件???????3948??2014-12-13?15:17??PolyphaseFilter\FilterDesign.asv

?????文件???????3859??2014-12-13?15:20??PolyphaseFilter\FilterDesign.m

?????文件??????13760??2014-12-13?15:07??PolyphaseFilter\input.wav

?????文件??????52974??2014-12-11?09:38??PolyphaseFilter\InputData.mat

?????文件??????48182??2014-12-13?14:33??PolyphaseFilter\output1.wav

?????文件??????48180??2014-12-13?14:33??PolyphaseFilter\output2.wav

?????文件??????70386??2014-12-13?10:19??PolyphaseFilter\六種窗函數(shù)特性表.jpg

?????文件????????139??2014-12-13?11:52??PolyphaseFilter\參考鏈接.txt

?????目錄??????????0??2016-09-20?15:52??PolyphaseFilter

-----------?---------??----------?-----??----

??????????????1165706????????????????????12