%實(shí)驗(yàn)二：時(shí)域采樣與頻域采樣
%時(shí)域采樣

%原信號(hào)
Tp=64/1000;%觀測(cè)時(shí)間64ms?
Fs=1000;??T=1/Fs;?
M=Tp*Fs;%取樣點(diǎn)數(shù)64點(diǎn)
n=0:M-1;t=n*T;
A=444.128;a=pi*50*2^0.5;w=pi*50*2^0.5;
xnt=A*exp（-a*t）.*sin（w*t）;
Xk=T*fft（xntM）;???%M=64點(diǎn)FFT[xnt]
figure（1）
subplot（421）;??plot（nxnt）;title（‘原信號(hào)波形‘）;
k=0:M-1;??wk=k/Tp;?
subplot（422）;plot（wkabs（Xk））;title（‘Fs=1KHz幅頻特性‘）;
xlabel（‘f/Hz‘）;ylabel（‘幅度（H1（jf））‘）;

%采樣頻率1KHz
Fs=1000;T=1/Fs;?%采樣頻率1KHz
M=Tp*Fs;%取樣點(diǎn)數(shù)64點(diǎn)
n=0:M-1;t=n*T;
A=444.128;a=pi*50*2^0.5;w=pi*50*2^0.5;
xnt=A*exp（-a*t）.*sin（w*t）;
Xk=T*fft（xntM）;???%M=64點(diǎn)FFT[xnt]
subplot（423）;??stem（nxnt‘.‘）;title（‘Fs=1KHz采樣序列‘）;
k=0:M-1;?wk=k/Tp;
subplot（424）;plot（wkabs（Xk））;title（‘Fs=1KHz幅頻特性‘）;
xlabel（‘f/Hz‘）;ylabel（‘幅度（H1（jf））‘）;

%采樣頻率300Hz
Fs=300;T=1/Fs;??M=Tp*Fs;n=0:M-1;t=n*T;
A=444.128;a=pi*50*2^0.5;w=pi*50*2^0.5;
xnt=A*exp（-a*t）.*sin（w*t）;
Xk=T*fft（xntM）;?
subplot（425）;?stem（nxnt‘.‘）;title（‘Fs=300Hz采樣序列‘）;
k=0:M-1;?wk=k/Tp;
subplot（426）;plot（wkabs（Xk））;title（‘Fs=300Hz幅頻特性‘）;
xlabel（‘f/Hz‘）;ylabel（‘（H2（jf））‘）;

%采樣頻率200Hz
Fs=200;T=1/Fs;??M=Tp*Fs;n=0:M-1;t=n*T;
A=444.128;a=pi*50*2^0.5;w=pi*50*2^0.5;
xnt=A*exp（-a*t）.*sin（w*t）;
Xk=T*fft（xntM）;?
subplot（427）;??stem（nxnt‘.‘）;title（‘Fs=200Hz采樣序列‘）;
k=0:M-1;??wk=k/Tp;
subplot（428）;plot（wkabs（Xk））;title（‘Fs=200Hz幅頻特性‘）;
xlabel（‘f/Hz‘）;ylabel（‘（H3（jf））‘）;

%=========================================================================%

%頻域采樣
M=27;N=32;n=0:M;
xn=（n>=0&n<=13）.*（n+1）+（n>=14&n<=26）.*（27-n）+（n<0|n>26）.*0;?????%產(chǎn)生x（n）
Xk=fft（xn1024）;??????????????????????????????????%1024點(diǎn)FFT[x（n）]?
k=0:1023;
wk=2*k/1024;?????????%連續(xù)頻譜圖的橫坐標(biāo)取值
figure（2）
subplot（321）;?plot（wkabs（Xk））;?title（‘FT[x（n）]‘）;
xlabel（‘w/\pi‘）;ylabel（‘|X（e^j^\w）|‘）;axis（[010200]）;
subplot（322）;?stem（nxn‘.‘）;?title（‘x（n）‘）;
xlabel（‘n‘）;ylabel（‘x（n）‘）;axis（[032020]）

k=0:N-1;????????????????%離散頻譜圖的橫坐標(biāo)取值
X32k=fft（xn32）;??????????????????????????????????%32點(diǎn)FFT[x（n）]
x32n=ifft（X32k）;??????????????????????????????????%32點(diǎn)IFFT[X32（k）]得到x32（n）
subplot（325）;stem（kabs（X32k）‘.‘）;title（‘32點(diǎn)頻域采樣‘）;
xlabel（‘k‘）;ylabel（‘|X_3_2（k）|‘）;axis（[0160200]）
n1=0:N-1;
subplot（326）;stem（n1x32n‘.‘）;title（‘32IDFT[X_3_2（k）]‘）;
k=0:N/2-1;?????????????%離散頻譜圖的橫坐標(biāo)取值?
X16k=X32k（1:2:N）;???????%隔點(diǎn)抽取X32（k）得到X16（k）
x16n=ifft（X16kN/2）;??%16點(diǎn)IFFT[X16（k）]得到x16（n）
subplot（323）;stem（kabs（X16k）‘.‘）;title（‘16點(diǎn)頻域采樣‘）;
xlabel（‘k‘）;ylabel（‘|X_1_6（k）|‘）;axis（[080200]）
n1=0:N/2-1;???????????
subplot（324）;stem（n1x16n‘.‘）;title（‘16IDFT[X_1_6（k）]‘）;
xlabel（‘n‘）;ylabel（‘x_1_6（n）‘）;axis（[032020]）
xlabel（‘n‘）;ylabel（‘x_3_2（n）‘）;axis（[032020]）

?屬性????????????大小?????日期????時(shí)間???名稱(chēng)
-----------?---------??----------?-----??----
?????目錄???????????0??2018-01-19?19:01??shuzixinhaochulishiyan\
?????文件????????2793??2017-12-27?15:11??shuzixinhaochulishiyan\exp2.m
?????文件????????2728??2017-12-27?21:04??shuzixinhaochulishiyan\exp3.m
?????文件????????4062??2017-12-27?20:48??shuzixinhaochulishiyan\exp3new.m
?????文件????????1844??2017-12-27?22:01??shuzixinhaochulishiyan\exp4.m
?????文件????????1825??2017-12-04?10:32??shuzixinhaochulishiyan\exp42.m
?????文件????????1127??2017-12-28?01:38??shuzixinhaochulishiyan\exp6.m
?????目錄???????????0??2018-01-19?19:01??shuzixinhaochulishiyan\matlab章節(jié)仿真\
?????文件???????11167??2017-12-10?23:01??shuzixinhaochulishiyan\matlab章節(jié)仿真\AH.ps
?????文件?????????264??2017-12-10?22:54??shuzixinhaochulishiyan\matlab章節(jié)仿真\p165.m
?????文件?????????270??2017-12-10?22:54??shuzixinhaochulishiyan\matlab章節(jié)仿真\p171.m
?????文件?????????263??2017-11-01?10:03??shuzixinhaochulishiyan\matlab章節(jié)仿真\p173.m
?????文件?????????258??2017-11-01?10:26??shuzixinhaochulishiyan\matlab章節(jié)仿真\p177.m
?????文件?????????279??2017-12-10?22:59??shuzixinhaochulishiyan\matlab章節(jié)仿真\P177a.m
?????文件?????????134??2017-12-10?23:08??shuzixinhaochulishiyan\matlab章節(jié)仿真\p177b.m
?????文件?????????231??2017-12-10?23:07??shuzixinhaochulishiyan\matlab章節(jié)仿真\p179.m
?????文件?????????207??2017-11-07?21:05??shuzixinhaochulishiyan\matlab章節(jié)仿真\p180.m
?????文件?????????482??2017-11-19?11:06??shuzixinhaochulishiyan\matlab章節(jié)仿真\p187.m
?????文件?????????552??2017-11-07?22:46??shuzixinhaochulishiyan\matlab章節(jié)仿真\p193.m
?????文件?????????245??2017-11-07?22:49??shuzixinhaochulishiyan\matlab章節(jié)仿真\p195.m
?????文件?????????175??2017-11-07?22:54??shuzixinhaochulishiyan\matlab章節(jié)仿真\p196.m
?????文件?????????332??2017-11-19?14:12??shuzixinhaochulishiyan\matlab章節(jié)仿真\p218.m
?????文件?????????452??2017-11-19?14:59??shuzixinhaochulishiyan\matlab章節(jié)仿真\p219.m
?????文件?????????344??2017-11-19?15:07??shuzixinhaochulishiyan\matlab章節(jié)仿真\p220.m
?????文件?????????839??2017-11-19?15:29??shuzixinhaochulishiyan\matlab章節(jié)仿真\p225.m
?????文件?????????724??2017-11-19?15:37??shuzixinhaochulishiyan\matlab章節(jié)仿真\p226.m
?????文件?????????427??2017-11-19?16:25??shuzixinhaochulishiyan\matlab章節(jié)仿真\p232.m
?????文件?????????467??2017-11-19?16:31??shuzixinhaochulishiyan\matlab章節(jié)仿真\p232b.m
?????文件?????????301??2017-10-16?07:56??shuzixinhaochulishiyan\matlab章節(jié)仿真\p69.m
?????文件?????????276??2017-10-16?08:00??shuzixinhaochulishiyan\matlab章節(jié)仿真\p71.m
?????文件?????????667??2017-10-16?09:52??shuzixinhaochulishiyan\matlab章節(jié)仿真\p82.m
............此處省略27個(gè)文件信息