中国大学Principles of Communication课后答案(mooc完整答案)
97 min read中国大学Principles of Communication课后答案(mooc完整答案)
Chapter 0 Unit Quiz
1、中国整答
2、大学
3、后答
4、案m案
5、中国整答
6、大学
Chapter 1 Random processes
Chapter 1 Unit Quiz 1
1、后答This 案m案random process X (t) =cos(2πfct). the frequencies can be 100, 200, . . . , 600 Hz，then:
A、中国整答The大学 possible values of X (0.001) could be cos(0.2π), cos(0.4π), . . . , cos(l .2π)，and each has a probability 1/6.
B、后答The案m案 possible values of X (0.001) could be cos(0.1π), cos(0.2π), . . . , cos(0.6π), and each has a probability 1/6.
C、The中国整答 possible values of X (0.001) could be cos(0.2π), cos(0.4π), . . . , cos(l .2π)
D、The大学 possible values of X (0.001) could be cos(0.1π), cos(0.2π), . . . , cos(0.6π)
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A、后答
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D、
3、Which one of the following functions can be the autocorrelation function of a random process?
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Chapter 1 Random processes
Chapter 1 Unit Quiz 2
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3、We have proved that when the input to an LTI system is stationary, the output is also stationary. If we know that the output process is stationary, can we conclude that the input process is necessarily stationary?
4、The process X (t) is defned by X(t) = X, where X is a randomvariable unifrmly distrbuted on [- 1, 1] , the autocorelation function and the power spectral density are: Rx(τ) = 1/3，Sx(f) = 1/3
5、Two random processes X(t) and Y(t) arejointly wide-sense stationar, then the cross-corelation RXY(t1, t2) depends ony on r = t1 - t2
6、Assume that Z(t) = X(t) + Y(t), where X(t) and Y(t) are jointly stationary random processes，then Sz(f) = Sx(f) + Sy(f)
Chapter 1 Random processes & Chapter 2 Continuous-wave modulation
Chapter 1 Test
1、Considering the properties of the autocorrelation function Rx(τ) of a random process X(t).
A、
B、
C、
D、
2、Considering the properties of the sine wave plus narrowband noise.
A、If the narrowband noise is Gaussian, the in-phase and quadrature components are jointly Gaussian.
B、Both the in-phase and quadrature component have the same variance.
C、Both the in-phase and quadrature component have the same mean.
D、The envelope and phase components are statistically independent.
3、
A、The mean of Y is 0.
B、
C、
D、Y is also Gaussian
4、
A、
B、
C、The power in X(t) is 4W.
D、The power in X(t) is 8W.
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8、Thermal noise is a stationary, zero-mean Gaussian process.
9、If two processes are statistically independent, they are orthogonal.
10、For stationary processes, means, variances and covariance are independent of time.
chap1 homework
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