基音周期提取，从而得到基频，改变基频可改变音调

function [periodperiod_freperiod_num]=pitch_period（yFsbits）
%filename =‘zhuoyin.wav‘;
%[yFsbits]=wavread（filename）;
%sound（w，fs，bits）播放w向量对应的声音
lefty = y（:1）;
wavesize=length（y）;

%================fir滤波========================%
b =[-0.0113    0.0242   -0.0222    0.0066    0.0201   -0.0274    0.0052    0.0346   -0.0475    0.0056...
0.0729   -0.1106    0.0059    0.5481    0.5481    0.0059   -0.1106    0.0729    0.0056   -0.0475...
0.0346    0.0052   -0.0274    0.0201    0.0066   -0.0222    0.0242   -0.0113];
[hw]= freqz（b1882）;
% waveout1 = filter（b1lefty）;
waveoutYuJiaZhong= filter（[1  -0.9375]1lefty）;
waveoutspeech = filter（b1lefty）;

%====================基音周期滤波=======================%
%2Khz低通hamming
b =[ 0.0054    0.0074    0.0130    0.0221    0.0341    0.0481...
    0.0628    0.0764    0.0874    0.0947    0.0972    0.0947...
   0.0874    0.0764    0.0628    0.0481    0.0341    0.0221...
    0.0130    0.0074    0.0054];
waveoutpitch = filter（b1lefty）;
%====================最大幅度=======================%
N=round（3*Fs/100）
between=floor（N/2）;
frameNumber =floor（wavesize/between）-1;
Tlefty=waveoutpitch ;
% Axiaobo=zeros（wavesize1）;
% 整个时域上的基音周期轨迹
pitch =zeros（1frameNumber）;
% 一帧中的自相关函数
R1=zeros（N1）;
%显示一帧自相关

for ii=1:frameNumber
        %
        startPositon=（between）*（ii-1）+1;
    %      startPositon=（between）*（ii-1）+1;