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1、1.解答源程序N=30,n=0:N-1,p=8,q=2,Xn=exp(-(n-p).2/q)Xk=abs(fft(Xn,N)figure(1)subplot(211)stem(n,Xn),grid ontitle(Xn)subplot(212)stem(n,Xk),grid ontitle(Xk)(1)p=8,q=2p=8,q=4p=8,q=8(2)q=8,p=8q=8,p=13q=8,p=14p=13时,发生明显泄露现象。无混叠解答源程序N=30,n=0:N-1,a=0.1,f=0.0625Xbn=(exp(-(a*n).*sin(2*pi*f*n)Xbk=abs(fft(Xbn,N)sub
2、plot(211)stem(n,Xbn),grid ontitle(Xbn)subplot(212)stem(n,Xbk),grid ontitle(Xbk)(1)a=0.1,f=0.0625(2)a=0.1,f=0.4375a=0.1,f=0.56253.解答:源程序N=8Xcn=0,1,2,3,4,3,2,1Xck=abs(fft(Xcn,N)subplot(221)stem(Xcn)title(Xcn)subplot(222)stem(Xck)title(Xck)Xdn=4,3,2,1,0,1,2,3subplot(223)stem(Xdn)title(Xdn)Xdk=abs(fft(X
3、dn,N)subplot(224)stem(Xdk)title(Xdk)(1)(2)补零后解答:源程序N=16,n=0:N-1,f=1/16Xn=sin(2*pi*0.125*n)+cos(2*pi*(0.125+f)*n)Xk=abs(fft(Xn,N)subplot(211)stem(n,Xn)subplot(212)stem(n,Xk)N=16,f=1/16N=16,f=1/64N=128,f=1/16N=128,f=1/645.解答线性卷积源程序N=16,n=0:N-1,p=8,q=2,a=0.1,f=0.0625Xan=exp(-(n-p).2/q)Xak=abs(fft(Xan,N)Xbn=(exp(-(a*n).*sin(2*pi*f*n)Xbk=abs(fft(Xbn,N)subplot(221)stem(n,Xak)title(Xak)subplot(222)stem(n,Xbk)title(Xbk)Ylk=Xak.*Xbkyn=ifft(Ylk)subplot(223)stem(yn)title(yn)线性卷积