考题是不泄露的。我上次考的，给点参考，见内1. COMMUNICATIONS: (a) AWGN noise passing through linear filter system, calculate and draw output autocorrelation function. Given t0, calculate PDF of w(t0), where w(t) is the output. (b) X(t) = A(t)cos(wt + B) where A(t) is a stationary random process and B is a uniformly distributed random variable in [0, 2pi]. Calculate the autocorrelation function and PSD of X(t). If A(t) = A and region of B is changed to [0, pi/2], calculate autocorrelation function again and the average power of X(t). COMMENTS: All the question is from the first 4 chapters in EE4102 - Digital Communications (Melissa Tao's part), which is actually the basic math knowledge of communication and is, to some extent, irrelevant to the major comm contents (modulation, optimum receiver, etc.) 2. SIGNAL PROCESSING: (a) h(n) = (a^-n)u(n), where u(n) is unit step function. a>1. Find DFT in terms of H(e^jw). Calculate |H(e^jw)|^2 and explain what will happen when 'a' becomes large. Let f(n) = [h(n (more...)