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# Rashtrasant Tukadoji Maharaj Nagpur University 2009 B.E Electronics & Communication Engineering Summer , Faculty of Engineering and Technology, LINE COMMUNICATION AND SWITCHING SYSTEM - Question P

Tuesday, 29 January 2013 06:00Web

part A

1. (a) provide the comparison of various Telegraphic codes.
(b) If the duration of smallest element in a telegraphic code is 20 msec. compute the speed in baud, characters per seconds and words per minute in
(i) Morse Code
(ii) Cable code
(iii) five unit synchronous code
(iv) 7.5 unit synchronous code

2. (a) define with the help of diagram of Teleprinter transmitter.
(b) discuss operate and release lag of a relay.

3. (a) discuss the importance of the subsequent terms as related to facsimile transmitter and receiver
(i) Index of cooperation
(ii) Phasing signal
(iii) Synchronizing signal
(b) discuss polarized relay

4. (a) elaborate the functions of transmission bridges? elaborate the different transmission bridge that obtain use in telephony? define any 1 with circuit diagram.
(b) define the method of signalling as employed in a Telax network for the establishment of local calls.

5. Write short notes on (ANY FOUR):
(i) five unit code
(ii) Morse sounder
(iii) Simplex circuit
(iv) Regenerative repeater
(v) Teleprinter Keyboard

part A

6. (a) define the various tones used in automatic exchange. elaborate their functions?
(b) discuss the subsequent terms as applied to a 2 motion selector:
(i) Vertical magnet
(ii) Rotary magnet
(iii) Off normal contacts
(iv) Wiper assembly

7. (a) Draw and discuss the trunking diagram of a 100 line exchange.
(b) Derive the relationship ranging from Numbers of Trunks availability (N), avg. traffic (A) and Grade of Service (B).

8. (a) A sending drum as a diameter of 66mm. compute the pitch and scanning speed of the sender and receiver if the receiver drum has a diameter of 88mm and the index of cooperation of the system is 352.
(b) discuss the difference ranging from the subsequent terms:
(i) Strawger and crossbar switching
(ii) Electronic and Electromechanical system.
(iii) Manual and automatic switching.

9. (a) elaborate directional filters? Do they possess any directional property?
(b) discuss the principle of long haul carrier telephone system in detail.
(c) describe "Busy hour" in automatic exchange.

10.Write short notes on (any FOUR):
(i) ISDN
(ii) Cellular Telephony
(iii) Subscriber Line Interface Circuit
(iv) Companding
(v) Inchannel signalling.