山东大学2011-2012学年2学期数字信号处理（双语）课程试卷(A) 号 三 四 五 七八 九 总分 阅卷人 3)If the poles of a system function H (z)are all in the unit circle,then the system is 得分 Directions图 A.absolutely stable: B.maybe stable and causal; C.absolutely causal; D.maybe stable but not causal 好 1)The answers of this test should be in English. 2)The full mark of this test is 100.The final course mark is based on this test (80%)and class 4)A Type II FIR Linear-Phase System can be used as a( 人 record mark (20%). 3)Tables of properties of Discrete-time Fourier transform,z-transform and DFT are supplied to A.low-pass filter, B.low-pass or high-pass filter, C.high-pass filter; D.neither low-pass nor high-pass filter; you on the last page. 4)Unless otherwise indicated,answers must be derived or explained,not just simply written down. 5)For a N-point DFT(N=2")of x[n],the total number of computations is the same for the 得分 卷人 decimation-in-frequency and the decimation-in-time algorithms,the number of complex (10 pts,2 pts for each)Choose the best answer to fill in the blanks. multiplications is( 的 A.mN; B.mN/2: C.N2; D.m2; 1)For a system for which the input and output satisfy a linear constant-coefficient difference equation,if the auxiliary information is in the form ofN sequential values of the output, then the system 舞分 阕卷人 2.(10 pts)The following figure shows the impulse response h[n] for a FIR LTI system. A.must be LTI and causal;B.may not be LTI;C.must be LTI but noncausal;D.is causal. 2)If the poles of the system function H(z)ofa LTI system are as in the Figure,and the 101 system is stable,then h[n]is a -14 1)Is the system generalized linear-phase system?Tell the reason.If the system is Unit cirele z-plane generalized linear-phase system,then determine which type of FIR linear-phase system it is.(It is known that there are four types of FIR linear-phase systems.) (5 pts) 2)Determine the group delay associated with the system.(5pts) 器 A.two-sided sequence (may be h[n]=a"u[n]+b'u[n]+c"u[-n-1])B.two-sided sequence (may behn]=bu[n]+c"u[-n-1]):C.right-sided sequence (may be 暴 h[n]=b'u[n]).D.left-sided sequence (may be hn]=c"u[-n-1]). 第1负共4页2011-2012 2 数字信号处理（双语） （A） 1 4 题号 一 二 三 四 五 六 七 八 九 十 总分 阅卷人 得分 Directions: 1) The answers of this test should be in English. 2) The full mark of this test is 100. The final course mark is based on this test (80%) and class record mark (20%). 3) Tables of properties of Discrete-time Fourier transform, z-transform and DFT are supplied to you on the last page. 4) Unless otherwise indicated, answers must be derived or explained, not just simply written down. 1．(10 pts, 2 pts for each) Choose the best answer to fill in the blanks. 1) For a system for which the input and output satisfy a linear constant-coefficient difference equation, if the auxiliary information is in the form of N sequential values of the output, then the system ( ). A. must be LTI and causal; B. may not be LTI; C. must be LTI but noncausal; D. is causal. 2) If the poles of the system function H (z) of a LTI system are as in the Figure, and the system is stable, then h[n] is a ( ). A. two-sided sequence (may be        1 n n n h n a u n b u n c u n = + + − − ); B. two-sided sequence (may be      1 n n h n b u n c u n = + − − ); C. right-sided sequence (may be     n h n b u n = ); D. left-sided sequence (may be    1 n h n c u n = − − ); 3) If the poles of a system function H (z) are all in the unit circle, then the system is ( ). A. absolutely stable; B. maybe stable and causal; C. absolutely causal; D. maybe stable but not causal 4) A Type II FIR Linear-Phase System can be used as a ( ). A. low-pass filter; B. low-pass or high-pass filter; C. high-pass filter; D. neither low-pass nor high-pass filter; 5) For a N-point DFT ( 2 m N = ) of x[n], the total number of computations is the same for the decimation-in-frequency and the decimation-in-time algorithms, the number of complex multiplications is ( ). A. mN; B. mN/2; C. N2 ; D. m2 ; 2．(10 pts) The following figure shows the impulse response h[n] for a FIR LTI system. 1) Is the system generalized linear-phase system? Tell the reason.If the system is generalized linear-phase system, then determine which type of FIR linear-phase system it is. (It is known that there are four types of FIR linear-phase systems.) （5 pts） 2) Determine the group delay associated with the system. （5 pts） 得分 阅卷人 得分 阅卷人