III B.Tech I Semester Supplementary Examinations, November 2006 DIGITAL COMMUNICATIONS ( Common to Electronics & Communication Engineering and Electronics & Telematics) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
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1. (a) A signal m(t) = 2 Cos (100πt) Cos (500πt) is ideally sampled at 700 Hz, and is sent through an ideal LPF with cut off at 650 Hz. Determine the frequency components in the filter output. What changes will be there if the sampling is done at Nyquist rate? [10]
(b) As applicable to pulse modulations systems, write short notes on Sampling theorem in frequency. [6]
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2. (a) How is PDM wave converted into PPM system?
[6]
(b) Explain why a single channel PPM system requires the transmission of Synchronization signal, where as a single channel PAM or PDM system Does not?
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[10]
3. (a) Prove that impulse response of the modified duo-binary filter consists of two sine functions that are time-shifted by 2 Tp seconds, and sketch its response.
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(b) A source emits one of three equiprobable symbols in an independent sequence at a symbol rate of 1000 bps. Design a three level PAM system to transmit the output of this source over an ideal lowpass channel with additive Gaussian noise having a PSD of η/2 = 10−14 Watt/Hz. The symbol error probability has to be maintained at or below 10−6 . Specify the power, bandwidth requirements and HT (f), HR (f) Pg (t). [8+8] 4. (a) Explain how eye patterns are used for monitoring the performance of base band PAM system. [8] (b) What is the necessity of shaping transmitted signal spectrum.
[8]
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5. (a) Draw the block diagram of PCM Generator and explain each block. (b) Determine the Transmission Bandwidth in PCM.
[8+8]
6. In a single-integration DM system, the voice signal is sampled at a rate of 64kHz.The maximum signal amplitude is Amax=1. (a) Determine the minimum value of the step size σ to avoid slope over load error. (b) Determine the granular noise power if the voice signals bandwidth is 3.5 kHz. (c) Assuming that the voice signal is sinusoidal, determine output signal power and SNR 1 of 2
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Code No: NR310405 (d) Determine the minimum transmission bandwidth.
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7. (a) Show that the probality of bit error of a matched filter receiver is given by √ Pe = 1/2 erfc Eb/No. [8]
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(b) Specify a matched filter receiver for the signal S(t) shown in Figure7b and Sketch the filter output as a function of time. [8]
Figure 7b
8. (a) Explain the systematic code form for the binary cyclic codes?
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(b) The generator matrix for (7,4) block code is given below
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i. Find the parity check matrix H of this code. ii. Show that these two matrices satisfy the condition CH T = 0. 1 0 0 0 1 1 0 0 1 0 0 0 1 1 G= 0 0 1 0 1 1 1 0 0 0 1 1 0 1
NR310405 III B.Tech I Semester Supplementary Examinations ...
4. (a) Explain how eye patterns are used for monitoring the performance of base ... Eb/No. [8] · (b) Specify a matched filter receiver for the signal S(t) shown in ...
8. The convolutional encoder is given below Figure1: · Figure 1: ... (b) Construct a code tree for the convolutional encoder for 3-bit input data. [10] · âââââ.
(b) The ground water level in a deposit of fine sand is 1.5 m below ground level. Above the water table ... is 21 kN/m3. Calculate the total stress, the neutral stress.
(b) Explain the following particle size measurement techniques. i. Sedimentation ... compaction. [6]. (b) Define Sintering and how is it different from hot pressing.
III B.Tech I Semester Supplementary Examinations, November 2005. AERO SPACE ... (b) Maximum energy theory. [16] ... plain with live examples. (b) Write a ...
4. What are the objectives of wage and salary administration function? [4+6+6] · 5. Write short notes on: · [4x4=16] · (a) Speculative purchasing · (b) Rate contract ...
(a) What are the different problems associated with measurement of low resis- · tances. Explain. (b) How these problems are eliminated by using Kelvins double ...
(b) What is score boarding and its use in RISC? [10] · 5. (a) Explain the salient features of Pentium architecture. [6] · (b) Draw the schematic blocks of Floating ...
Which one you are saving by using statistical time-division multiplexing and prove · it. [16M] · 8. Give two full duplex protocols and explain their operation? [16M].
(a) Pattern plating process. (b) Tenting process. [8+8] · 7. (a) Draw the schematic diagram of magnetic amplifier with a center tapped trans- · former and D.C. ...
A reversible engine operating between a reservoir at 600 K and the ambient at- · mosphere at ... Determine the ratio of energy rejected by both the devices to the.
What is degree of reaction of a gas turbine; how it can be controlled, derive its ... A single stage free vortex turbine is designed for zero degree of reaction at root.
(b) Discuss the help of computers in Cardio vascular evaluation in ICU. [8] · 7. Discribe the use of computers for handicapped persons. Give two examples and.
(a) Explain the pre-anesthetic care and preparation undertaken in a hospital. Why it is important? Explain. [8] · (b) How the patients are monitored during surgery ...
III B.Tech I Semester Supplementary Examinations, November 2005. POWER ELECTRONICS · (Electrical & Electronic Engineering) · Time: 3 hours · Max Marks: 80 · Answer any FIVE Questions · All Questions carry equal marks · ***** · 1. (a) Explain the oper
(c) Explain inverted paging method of memory management. [4+4+8] · 4. (a) Explain banker's algorithm for deadlock detection. (b) What are the criteria for a ...
(a) Discuss the path sensitization in a combinational circuit. shown in figure1 · (b) Find the test set to detect A1- SA0 and A1- SA1 faults using Boolean difference.
i. plain carbon steel with 4% carbon and 0.8% manganese, ... (a) It is required to design a square key for fixing a gear on a shaft of 30 mm · diameter; to transmit ...
TECHNIQUES OF METAL JOINING · (Metallurgy & Material Technology) · Time: 3 hours · Max Marks: 80 · Answer any FIVE Questions · All Questions carry equal ...
Figure 1 shows two views of a tripod bracket. All connections are pinned. Find · the forces in magnitude and nature in the three memebers due to a vertical load ...
(b) Explain the bridge type of thermocouple arrangement and mention its ... 3. The standard resistor arm of a Wheatstone bridge has a range from 0 to 100 ohm.
