155. The energy-density spectrum of a signal represents
A. energy per unit bandwidth
B. relative contribution of energy by positive components
C. relative contribution of energy by negative components
D. all of the above

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156. The unit of energy density spectrum is
A. Hz/J
B. H/Hz
C.H
D. J

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157. With reference to which of the following, the effect of noise in a communication system is most adverse?
A. Receiver
B. Channel
C. Source
D. Encoder

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158. What is the total area under probability distribution curve?
A. Zero
B. One
C. Infinite
D. None of the above

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159. Autocorrelation, for a Gaussian process, also implies
A. ergodic process
B. statistical dependence
C. statistical independence
D. none of the above

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160. In communication, an ergodic process is present if many random signals have
A. identical time and ensemble averages
B. identical time averages
C. identical ensemble averages
D. none of the above

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161. In carrier system frequency frogging is used to
A. reduce cross talk
B. reduce distortion
C. conserve frequencies
D. all of the above

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