Uttar Pradesh Technical University (UPTU) 2007 B.E Electronics & Tele-Communication Engineering ELECTRONICS SWITCHING - Question Paper

B.tech
7th semester examination, 2007-2008
ELECTRONICS SWITCHING

TIME=3 HOURS TOTAL MARKS=100

Q.1. Attempt any 4 parts of the subsequent ques.. (5×4=20)

(a) Draw the elements of a switching system and trunking diagram and discuss its function.

(b) Why is electronic exchange alone suitable for digital telephony? discuss.

(c) With help of suitable diagram define the working of a crossbar exchange.

(d) Give the classification of switching system. Compare the switching technique used in PSTN.

(e) What do you understand by blocking and nonblocking model of telephone traffic? Draw NXN 3 stage switching network.

(f) Find the delay in sending an X bit message over a K hop path in a circuit switched network. The circuit setup is ‘S’ second, the packet size is P bits and the data rate is B bps.


Q.2.Attempt any 4 parts of the subsequent ques.. (5×4=20)

(a) With the help of neat diagram discuss the operation of TSL. Compare TSI with space switching.

(b) Consider a three stage crossbar switch system with 1000 input and 1000 output lines. It is nonblocking. For a optimum design ,what is the total number of cross points required? How many arrays are needed for every stage?

(c) For a TST switch with a single stage space switch determine the number of crosspoints and the total number of memory bits needed if the number lines is 32, number of channel per frame is 30 and time expansion is 2.

(d) How many time slot interchange modules are needed for an STS switch with 128 primary TDM signals of 30 voice channels per input ? presume blocking to be less than .002 and the loading is .2 Eriang per channel and determine the complexity of the switch .

(e) Can you built a switch with a single TSI which can handle 120000 calls with a DRAM access time of around 80 ns? discuss.

(f) Explain the necessity of combination switch.

Q.3. Attempt any 4 parts the subsequent question: (5×4=20)

(a) Explain the modeling of a telephone traffic system as birth –death process.

(b) What is meant by call congestions in a telephone network? During a busy hour, 1400 calls were offered to a group of trunks and 14 calls were lost .the avg. call duration has three minutes.

Find: (i)GOS (ii) the total duration of period of congestion.

(c) Compare loss system and delay system with improper example. In limit all delay system behaves like loss system. How?

(d) Using Lee’s graph for a 3 stage networks describe switching elements advantage ratio ? and obtain out the number of switching elements S for N=128.

(e) Explain the difference ranging from micro programmed control and hard –wired control schemes for Electronics control.

(f) What are the different sub system in a telephone network? What is BORSHT?

Q.4.Attempt any 2 parts of the subsequent ques.. (10×2=20)

(a) Explain Centralized SPC with the concept of dual processor architecture modes and distributed SPC with levels processing used in dual chain distributed control.

(b) (i) discuss the x-25 interface with neat diagram.

(ii) discuss the important features and frame structure of HDLC.

(c) Discuss the different signaling techniques used in telephonic networks discuss common channel signaling with SS7 architecture.

Q.5. Attempt any 4 parts the subsequent question: (5×4=20)

(a) Explain the call establishment/release process in ATM using virtual channel and Virtual paths .

(b) Draw TCP/IP reference model. How IP addressing is achieved? With reference to IP, explains the address resolution protocol.

(c) Draw a 16×16 banyan switching fabric. Where is header translation done in a multicast ATM switch?

(d) What do you mean by bad rates and bit rates? What is the maximum data rate achievable, if a binary signal is sent over a three kHz channel whose S/N ratio is 40 dB?

(e) How is constant bit rate achieved in ATM? Why is cell-delay variation due to network, minimum in ATM.

(f) Explain hoe the data can be transmitted over public switched telephone networks. why is frame relay a better solution for connecting LAN’s than T1 lines.




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Earning:   Approval pending.