| COMMUNICATION SIGNALS AND SYSTEM |
| PAPER NO. 1 |
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| PUT ON: 4th June, 2K3 |
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EC-202 COMMUNICATION SIGNALS AND SYSTEM (B.Tech 4th Semester,2063) Time : 3 Hours Maximum Marks : 60 NOTE:- This paper consist of Three Sections. Section A is compulsory. Do any Four questions from Section B and any two questions from Section C Section-A Marks : 20 1(a) Define a stochastic process. (b) Define cross-correlation function. (c) What is auto-correlation function of a ststionary process X(+)? (d) What is the power density spectrum of a single? (e) Define sampling theorm. (f) What is the difference between thermal and non-thermal emmision? (g) List all types of internal noise. (h) Describe stationarity of non-transients. (i) What is the relationship between the internal noise of electronic equipment and the noise figure? (j) What is the physical significance of a matched filter? Section-B Marks:5 Each 2. Determine the noise power (Pn) and noise voltage (Vn) of a circuit operating at a bandwidth of 5 MHz and temperature of 420 K with a load of 1 Mω. Assume an ideal noise source. 3. Derive the relations for cross-correlation and non-covariance function for a joint stochastic processes. 4. Explain the characteristics of the probability density function of Gaussian distribution. 5. Describe the relation between equilent noise temperature and noise power. 6. What is power Density Spectrum of perodic signals? Describe Parseval's relation for power signals. Section-C Marks : 10 Each 7. Determine the fourier series and power density spectrum of the rectangular pulse train signal shown in Figure.  8. Discuss the properties of the Matched filter and give the necessary proofs. 9. Determine the noise figure of a microwave amplifier operatring with a bandwidth of 27 MHz and internal noise power of 1 X 10-13 W. |