Region of convergence (ROC) X(z≤∑x[n]lz"<o, z=rew n=-00 Convergence of the z-transform for a given sequence depends only on r=z z-plane if some value of z,say, unit circle Z =Z1,is in the ROC, then all values of z on the circle defined by =zil 欧e will also be in the ROC. 傅里叶变换一致收敛uniform convergence 设z=|z1=1 在收敛域内 if ROC includes unit circle,then Fourier transform and all its derivatives with respect to must be continuous functions ofz1 if some value of z, say, z =z1 , is in the ROC, then all values of z on the circle defined by |z|=|z1 | will also be in the ROC. if ROC includes unit circle, then Fourier transform and all its derivatives with respect to  must be continuous functions of . ( )   , - n n X z x n z  − =      ◆Convergence of the z-transform for a given sequence depends only on r z = . Region of convergence (ROC) j z re  = 傅里叶变换一致收敛uniform convergence 9 设|z|=|z1 |=1 在收敛域内 unit circle