INDIAN RAILWAY QUESTION BANK FOR SIGNAL AND TELECOMMUNICATION

Published by Roma Rahul Gupta for Chhattisgarh Online
INDIAN RAILWAY QUESTION BANK FOR SIGNAL AND TELECOMMUNICATION

TELECOMMUNICATION - PART I

1) What is the advantage of DTL MUX over conventional ITI MUX? 2) According to the CCITT recommendations, how the basic group is onstructed? Explain with diagram? 3) In DTL MUX, what are the steps involved to translate a low frequency voice channel to high frequency of band 60 to 552 KHz ? 4) Write short notes on any two of the following: a) Channel modem b) VFT card c) Base band combiner Board. 5) What are the basic requirements of PCM system? Explain about sampling? What is a frame and multi-frame? Explain about multi-frame? 6) List out the factors to be considered for selecting a site for a microwave station. 7) What do you understand by the terms non-fade level, fade margin and threshold level. Briefly explain each of them. 8) What are the merits and de-merits of frequency diversity system over space diversity system? 9) Explain working of SPC exchange with a functional block diagram 10) Draw the basic block diagram of an ELECTRONIC TELEPHONE and explain its working. 11) List out the features of any electronic exchange and explain any five features 12) What are the different types of modulation techniques and explain balance modulator? 13) Expalin about positive and negative feed back? Explain advantages of negative feedback in amplifiers 14) Write short notes on any Three i) Phase lock loop ii) Automatic gain control (AGC) iii) Varactor Diode iv) Step Recovery diode v) Mixer in Receiver 15) What do you understand by hybrid circuit? Describe the audio range bybrid function in full detail with diaram 16) What are the precautions to be taken while loading the RE main telecom cable drums? How cable is laid on culverts and bridges? 17) What are the different types of RE cable joints? Explain the function of loading coil joint and condenser joint? 18) What are the periodical tests to be carried out on underground cables and give the accepted value? 19) Write the quad allocation for 6-quad cable and give its electrical characteristics? 20) What are the periodical tests to be conducted on RE cable circuits and explain the procedure for each? Write about emergency control in RE area 21) Explain the working of Section Control in RE area with the help of a Schematic diagram? 22) Draw the simplified circuit diagram of 2W control telephone and explain its working? 23) Descibe the basic differences between AM and FM receivers 24) What is the purpose of limiter in FM receiver? 25) List out different antenna used in railway communication. 26) Draw the block diagram of a 7GHz Digital Radio and explain briefly? 27) What are the differences between Analog and Digital MW systems? 28) Draw the block diagram QPSK modulator and explain briefly? 29) Write short notes on any THREE of the following: a) TXDPU b) SWO & SWO Central Card c) RXDPU d) Measurements on Digital Radio 30) Draw the block diagram of 7D15 Radio equipment, and explain the type of switching employed in 100% standby mode briefly? 31) Write the advantages of Harris Radio equipment over 7D15. Write the significance of OSCMOD and Harmonic Mixer in the transmitter section of HARRIS Radio equipment? 32) State the salient features of 7D20 radio equipment. Describe the function of DEV 34 MODULATOR unit in 7D20 Transmitter? 33) Write short notes on: 1) Receive local oscillator of 7D20. 2) Injection lock amplifier (ILA). 3) PLL circuit of Harris Transmitter. 4) Fresenal zone 5) K Factor 6) Polarisation 34) Explain the call processing in CDOT 128 P RAX? 35) Draw the block diagram of CDOT 128P RAX and briefly explain each block? 36) Explain briefly about the difference circuit cards used in CDOT 128P PBX? 37) Explain briefly about SLICA, SLICEE, LSLIC in OKI exchange? 38) What is the use of Attendant Console used in OKI exchange? List out features of attendant console? 39) Write short notes: i) Two frequency plan ii) fresnel zone. Iii) folded dipole antenna iv) K-factor. 40) Define any two of the following: i) Beamwidth ii) Antenna gain iii) Isotropic iv) skip distance. 41) Draw the functional block diagram of SPC exchange and mention the working of Each block. 42) Explain call processing in any telephone exchange. 43) Draw the block diagram of push button telephone and explain each block. 44) List out the special features of electronic exchange. 45) List out the wave guide devices used in microwave communication with their usages 46) What are the periodical tests to be carried out for U/G RE cable? 47) What are the different types of cable joints used for RE cable? Explain what is loading section. 48) How Telecom cable is protected on culverts and bridges? 49) What are the precautions to be taken while cable laying? 50) What daily maintenance you will carry out for diesel engine? 51) Describe the power supply arrangement provided in MW station with block diagram? 52) Write five advantages of SMPs over conventional power supply? 53) Explain the function of anyone of the microphone with necessary diagram and also explain its characteristics? 54) What are the requirements needed to install a PA system for platform announcement? 55) Briefly explain the PA system arrangements for conference hall. 56) Give the list of materials that are kept in ARTs ? 57) Give the periodicity of testing BD SPLs by different staff ? 58) What are the arrangements made at accident spot when the accident occurs in underground cable area? 59) What is the essential difference between ISDN and normal telephone system? Explain briefly BRI, PRI and NT. 60) What are the advantages of ISDN? 61) What are the faults in PRS system and what are the different types of tests to be conducted to isolate the faults? 62) Explain IVRS system with a simple block diagram? Write short notes on: a) Statistical Multiplexer. b) Modem c) LDR d) Router. 63) Explain briefly about SLICA, SLICEE, LSLIC in OKI exchange. List out any 12 cards used in CME rack. 64) What is the use of Attendant Console used inOKI exchange? List out features of attendant console? 65) Explain how a CO call is connected to a local extension in OKI exchange? 66) Explain principle and operation of a dynamic microphone with a neat diagram. 67) What is the need for matching in PA system. Explain voltage matching method with necessary diagram. 68) Explain platform announcement system for a 4 Nos of platforms of 1 KM each. 69) What is meant by UPS? Name the three types of UPS and explain any one of them with block diagram? Give it uses? 70) What are the advantages of SMPS over linear power supply? Explain briefly working of SMPS with block diagram. 71) Write short notes on: a) Power supply arrangement at MW station. b) Difference between three types of UPS c) Voltage regulator d) VRLA battery e) Initial charging of lead acid battery 72) What are the advantages and disadvantages of SMPS over conventional power plants? 73) What are the maintenance requirement for conventional lead acid batteries ? 74) Write the different types of battery charging and where they are used? 75) What are the precautions to be taken for battery room? 76) Write the procedure of initial charging of a lead acid battery and write the precautions to be taken during charging? 77) Write the maintenance to be carried out for lead acid battery? Explain how you will attend a sulphated lead acid cell? 78) Write what precautions you will take to avoid defects in lead acid battery? Draw the simple type of battery charger block diagram and explain function of each stage? 79) Explain with a neat sketch how the tapping for a way station is done in a 4- wire DTMF Control communication system. 80) Explain with a block diagram the working of DTMF decoder used in way station. 81) Explain the working of an auto dialling system and how it is used in control working? 82) What are the different types of main telecom cable joints used in RE area? Explain the function of each joint. 83) What are the periodical tests to be conducted in RE main telecom cable? 84) What are the precautions to be taken for cable jointing? 85) Draw and explain the functional block diagram of SPC Exchange. 86) What do you know about electronic exchanges and different circuits used in any electronic telephone exchange? Briefly explain. 87) Explain what do you understand by Conference facility in an exchange. 88) What are the functions of MDF? 89) What are the protection arrangements done in an exchange? 90) What would be the role of a railway servant in the case of train accident, when he/she is traveling in the same train? 91) What would be the role of the testroom during an accident of passenger train? 92) Why earth is required ? Give five points in support of your explanation. 93) Explain with schematic diagram the principle of SMPS based power plants.

TELECOMMUNICATION - PART II ESTABILISHMENT, STORES AND OFFICIAL LANGUAGE:

1) What is a Duty Pass? Explain the occasions for which different types of duty passes are issued to an Railway employee? 2) What is a Metal Pass? Explain the eligibility conditions? 3) What is the procedure of availing the Special CL? On which occasions the special CL can be sanctioned? 4) Write about Study Leave? 5) What is meant by Suspension? List out the entitlements during suspension? 6) What are the Minor Penalties that can be imposed on an Railway employee? 7) Give the classification of Railway employees under HOER. Mention the Rostered hours, statutory hours, and rest period for each? 8) What are the questions to be asked during the Preliminary Inquiry ? 9) List out the Minor and Major penalties and Disciplinary and Appeal rules as applicable to railway servents 10) Distinguish between Appointing Authority and Disciplinary Authority 11) What is workmans compensation act and to whom it applies? 12) Describe the various stores to be maintained by JE-Tele with accountal? 13) Write the following: a) Scrap Disposal. b) MAS account. c) DMTR d) PAC e) Non-stock requisition 14) Explain the following: a) Objectives of stock verification. b) Periodicity of SV. c) Method of SV. d) What is stock sheet? 15) Write short notes on the following: a) Classification of Railway expenditure. b) Charged expenditure. c) Budget estimates. 16) What are the different types of Tenders and explain? 17) What is meant by EMD & SD ? Who will pay and explain with rates? 18) What is M.B. and how M.B. is filled? Explain with example. 19) Write 10 points on the DOs and Donts in execution of work from vigilance angle 20) What are the different type of stores to be maintained by an SE/Tele? Give the purpose, scale accountal of each type. 21) What is the need for stock verification? Give the types and explain how the stock verification is done? 22) What is single tender and when it is done? 23) What are the different steps taken by Railways to implement use of Hindi in official work 24) What incentives are given for passing various Hindi examinations? 25) What are the incentives for the use of Raj bhasha ? 26) According to official language group, with how many regions India is divided ? Mention the Different states under each region ?

TELECOMMUNICATION - PART III

CHOOSE THE CORRECT ANSWER 1) Number of PTOs eligible by Railway servant in a calendar year are A) 1 B) 2 C) 4 D) 6 ( C ) 2) Leave not due during entire service shall be limited to a maximum o A) 24 months B) 48 months C) 360 Days D) 4 months ( C ) 3) Group D staff retired after 20 years of service will get the following sets of passes A) 2 B) 1 C) 3 D) NIL ( B ) 4) Joining time eligible when the distance is below 1000 KM is A) 10 days B) 12 days C) 15 days D) Nil. ( A ) 5) The output stage of a practical amplifier is always - - - coupled A) R-C B) Transformer C) L.C ( B ) 6) R.C coupling is used for - - - amplification A) Voltage B) Current C) Power ( A ) 7) A Zener diode is operated in the - - - -region A) Breakdown Region B) Forward characteristic region ( A ) C) Reverse characteristic region 8) A Zener diode is used as - - - A) Rectifier B) Voltage regulator C) For both ( B ) 9) A Transistor has - - - PN junctions A) One B) Two C) Three ( B ) 10) Common collector arrangement is generally used - - - A) Impedance matching B) Voltage matching C) None of the above ( A ) 11) The most commonly used transistor circuit arrangement - - - A) Common base B) Common emitter C) Common collector ( B ) 12) The function of Transistor is to do - - - A) Rectification B) Amplification C) None of the above ( B ) 13) Amplifiers are coupled to - - - - A) Increase gain B) Reduce noise C) For both ( A ) 14) If three stage amplifiers has individual stage gain of 10 db, 5 db & 12 db then the total gain A) 600 db B) 7 db C) 27 db ( C ) 15) Output transformer is always a - - - - transformer A) Step down B) Step up C) Both ( A ) 16) Negative feed back reduces - - - - in amplifiers A) Distortion B) Stability C) None of the above ( A ) 17) Positive feed back used in - - - - A) Oscillators B) High gain amplifiers C) Rectifiers ( A ) 18) An Oscillator produces - - - oscillations A) Damped B) Undamped C) Both ( B ) 19) Tuned amplifiers are used for - - - - frequency amplification A) Audio B) Radio C) For both ( B ) 20) Detection is done in - - - - A) Radio transmitter B) Radio receiver C) None of the abov ( B) 21) Frequency modulation gives - - - noise A) More B) Less C) No noise ( B ) 22) Ground plane antenna are used for A) VHF B) UHF C) MW D) HF ( A ) 23) In AM wave, useful power is carried by - - - A) Carrier B) Side bands C) Both of the above ( B ) 24) Superhetrodyne principle provides selectivity at - - - stages A) RF B) IF C) None of the above ( B ) 25) A switch has - - - states A) One B) Two C) Three ( B ) 26) A circuit that generates square wave is called - - - A) Amplifiers B) Multi vibrators C) Flip-flop ( B ) 27) A FET is essentially a - - - - driven device A) Voltage B) Current C) Both ( A ) 28) A FET is a - - - transistor A) Bi-polar B) uni-polar C) None of the above ( A ) 29) An SCR has - - - PN junctions A) One B) Two C) Three ( C ) 30) If firing angle in SCR increases, output is - - - A) Increases B) Decreases C) No change ( B ) 31) An SCR is a - - - switch A) Uni-directional B) Bi-directional C) None of the above ( A ) 32) A Triac is a - - - power switch A) Uni-directional B) Bi-directional C) None of the above ( B ) 33) A Triac has - - - terminals A) One B) Two C) Three ( C ) 34) A UJT has - - - PN Junction A) One B) Two C) Three ( A ) 35) A Diac is an - - - switch A) AC B) DC C) Both the above ( A ) 36) ICs are generally made of - - - A) Silicon B) Germanium C) None of the above ( A ) 37) Binary means - - - Binary numbers have a base of 2 A) One B) Two C) Three ( B ) 38) The digits used in a binary number system are A) 0 & 0 B) 0 & 1 C) 1 & 1 ( B ) 39) A Byte is a string of - - - Bits A) 16 B) 8 C) 2 ( B ) 40) A typical Microcomputer have - - - registers in memory A) 4096 B) 2048 C) 65536 ( C ) 41) A Gate is a logic circuit with one or more inputs, but only - - - output A) One B) Two C) Three ( A ) 42) The - - - gate has one or more high inputs, produces high output A) NOT B) OR C) XOR ( B ) 43) Which is the logic gate, where all input signals must be high to get a high output A) AND B) OR C) NOT ( A ) 44) In a NOR gate all inputs must be - - - to get high output A) Low B) High C) None of the above ( A ) 45) A NAND gate is equivalent to an - - - gate followed by an inverter A) AND B) OR C) NOR ( A ) 46) What is ISDN? A) Integrated Services Data Network. ( D ) B) Internal services digital network. C) International services data networks. D) Integrated services digital network 47) For making outgoing calls, what is the tone heard when the telephone handset is lifted A) Busy tone B) Dial tone C) No tone D) Ring back tone ( B ) 48) What is the break down voltage suggested for lightening dischargers (LD) in the MDF of telephone exchanges A)230 V B)160 V C)300 V D)1600 V ( A ) 49) What is the basic function of a telephone exchange? A)Signaling B) Switching C) Control D) All the above ( D ) 50) What is the control system used in Electronic exchange A) Stored program control B) Wire logic control ( A ) C) Electromagnetic control D) None of the above 51) The maximum number of subscriber lines in C-DOT 128P RAX type exchange is A)104 B) 112 C)96 D)88 ( D ) 52) The duplication system employed for the PSU card of an electronic exchange is A)Passive standby B)Load sharing standby C)N+1 Redundancy ( B ) D)None of the above 53) is the object of earthing for telecommunication equipment A) to provide a return earth B) To provide safety against shack to the working person ( D ) C) to provide protection against unduly high voltages D) all the above 54) What is the earth electrode called ( C ) A) A wire buried in to the earth nearby the equipment B) An iron rod buried I to the earth near the equipment C) A metal plate electrically connected to the general mass of the earth D None of the above 55) What is the maximum limit of earth resistance for Telecom equipment A) 10 ohms B) 5 ohms C) 2 ohms D) 1 ohm ( D ) 56) How the telecom equipment is connected to the earth electrode ( A ) A) by using earthing lead B) by keeping the equipment close to the electrode C) by using capacitors D) None of the above 57) What are the materials used to prepare an efficient earth for telecom equipment ( A ) A) coke, crushed coal and common salt B) plastic waste, thermo coal and glass pieces C) wood saw dust, white cement and asbestos powder D) wax, petroleum jelly and castor oil 58) In Microwave station which lead of the charger is earthed A) negative B) positive C) None of the above ( B ) 59) The maximum number of way stations can be in a control section using 2- digit code are A) 60 B) 99 C) 100 D) 90 ( B ) 60) DTMF control equipment works on A) 24 Volts B) 12 Volts C) 48 Volts D) 230 Volts ( B ) 61) Nominal ringing period at way station is A) 4 seconds B) 8 seconds C) 12 seconds D) 1 minute ( A ) 62) No. of 20 watts loud speakers permitted to connect an 250 watt amplifierare ( C ) A ) 5 B) 15 C) 12 D) 20 63) Block circuits in RE area works on ( C ) A) MW patch B) VF quad C) PET quad D) Carrier quad 64) To increase the ampere hour capacity of secondary cells, the cells are to be connected in A) Series B) Parallel C) Series and Parallel D) One above the othe ( B ) 65) No. of cable pairs required for 4 wire E&M working are ( C ) A) One B) Four C) Three D) Six 66) Duplexer is used for ( D ) A To couple two different antennaes B) To prevent interference between two antennas C) To increase the speed of transmission D) To allow one antenna to be used for reception and transmission 67) Inverter convert ( B ) A) AC to DC B) DC to AC C) DC to DC D) AC to AC 68) For converting 2 wire to 4 wire the following is required ( C ) A) Low pass filter B) High Pass filter C) Hybrid D) All these 69) In EC socket the transformer used have the impedance ratio ( D ) A) 2:1 B) 1120 : 1120 C) 470 : 1120 D) 1120 : 600 70) In a hybrid transformer the loss is ( B ) A) 2 db B) 3db C) 4 db D) No loss 71) A power amplifier gives a gain of 3 db when the input is 1 W the output is: ( B ) A) 1.3W B) 2 W C) 3 W D) .3 W 72) Grid antenna is used in ( C ) A) MW B) VHF C) UHF D) HF 73) Hybrid transformer is used in the following electronic exchange card ( D ) A) LCC B) SPC C) TIC D) TGT 74) In electronic exchange the system software is written as ( D ) A) E PROM B) E2 PROM C) RAM D) ROM 75) Which of the electronic exchange card is not redundant. ( B ) A) X SC B) LCC C) PSU D) RGD 76) The processor used in a C DOT exchange is ( A ) A) 65 CO2 B) 8085 C) Z80 D) 8031 77) Control card used in C DOT exchange is ( D ) A) SPC B) TIC C) RCT D) All the above. 78) RE repeater are spaced at every ( B ) A) 17 KM B) 40 KM C) 60 KM D) 1860 M 79) The insertion loss of way station control telephone is ( C ) A) 3 db B) 2 db C) 0.2 db D) 0.5 db. 80) The charectristic impedance of PET quad pair is -------------- ( B ) A) 600 Ohms B) 470 Ohms C) 1120 Ohms 81) The loading coil section in RE cable is ( A ) A) 915 m B) 1830 m C) 530m 82) Which of the MW frequency spectrum is used for Railway administration trunks ( B ) A) 4125 4425 MHz B) 7125 7425 MHz C) 1200 1600 MHz 83) The size of RE cable having 2 PET and 12 VF quad is represented as ( C ) A) 2 + 0 + 12 B) 0 + 2 + 12 C) 0 + 12 + 2 D) 0 + 14 84) Float charge voltae adjusted per cell in ( A ) A) 2.16 V B) 2.4 V C) 1.8 V 85) Beta in grounded emitter circuit is very high due to ( B ) A) base current is equal to collector current B) base current in small compared to collector current C) base current is higher than collector current 86) A metallic sheath is provided in RE cable to ( B ) A) to reduce cross-talk B) to reduce induce voltage C) to reduce weight of the cable 87) In RE cable the insulation resistance will be ( C ) A) less than 10 mega ohms B) more than 10 mega ohms C) above 20 mega ohms 88) Loud Speakers are always connected in parallel on ( C ) A) Voltage Matching B) Impedance Matching C) Both of them D) None of them

INDIAN RAILWAY QUESTION BANK  SIGNAL & TELE PART IV

OBJECTIVE QUESTIONS.

CHOOSE THE CORRECT ANSWER 1) Number of PTOs eligible by Railway servant in a calendar year are A) 1 B) 2 C) 4 D) 6 ( C ) 2) Leave not due during entire service shall be limited to a maximum o A) 24 months B) 48 months C) 360 Days D) 4 months ( C ) 3) Group D staff retired after 20 years of service will get the following sets of passes A) 2 B) 1 C) 3 D) NIL ( B ) 4) Joining time eligible when the distance is below 1000 KM is A) 10 days B) 12 days C) 15 days D) Nil. ( A ) 5) The output stage of a practical amplifier is always - - - coupled A) R-C B) Transformer C) L.C ( B ) 6) R.C coupling is used for - - - amplification A) Voltage B) Current C) Power ( A ) 7) A Zener diode is operated in the - - - -region A) Breakdown Region B) Forward characteristic region ( A ) C) Reverse characteristic region 8) A Zener diode is used as - - - A) Rectifier B) Voltage regulator C) For both ( B ) 9) A Transistor has - - - PN junctions A) One B) Two C) Three ( B ) 10) Common collector arrangement is generally used - - - A) Impedance matching B) Voltage matching C) None of the above ( A ) 11) The most commonly used transistor circuit arrangement - - - A) Common base B) Common emitter C) Common collector ( B ) 12) The function of Transistor is to do - - - A) Rectification B) Amplification C) None of the above ( B ) 13) Amplifiers are coupled to - - - - A) Increase gain B) Reduce noise C) For both ( A ) 14) If three stage amplifiers has individual stage gain of 10 db, 5 db & 12 db then the total gain A) 600 db B) 7 db C) 27 db ( C ) 15) Output transformer is always a - - - - transformer A) Step down B) Step up C) Both ( A ) 16) Negative feed back reduces - - - - in amplifiers A) Distortion B) Stability C) None of the above ( A ) 17) Positive feed back used in - - - - A) Oscillators B) High gain amplifiers C) Rectifiers ( A ) 18) An Oscillator produces - - - oscillations A) Damped B) Undamped C) Both ( B ) 19) Tuned amplifiers are used for - - - - frequency amplification A) Audio B) Radio C) For both ( B ) 20) Detection is done in - - - - A) Radio transmitter B) Radio receiver C) None of the abov ( B) 21) Frequency modulation gives - - - noise A) More B) Less C) No noise ( B ) 22) Ground plane antenna are used for A) VHF B) UHF C) MW D) HF ( A ) 23) In AM wave, useful power is carried by - - - A) Carrier B) Side bands C) Both of the above ( B ) 24) Superhetrodyne principle provides selectivity at - - - stages A) RF B) IF C) None of the above ( B ) 25) A switch has - - - states A) One B) Two C) Three ( B ) 26) A circuit that generates square wave is called - - - A) Amplifiers B) Multi vibrators C) Flip-flop ( B ) 27) A FET is essentially a - - - - driven device A) Voltage B) Current C) Both ( A ) 28) A FET is a - - - transistor A) Bi-polar B) uni-polar C) None of the above ( A ) 29) An SCR has - - - PN junctions A) One B) Two C) Three ( C ) 30) If firing angle in SCR increases, output is - - - A) Increases B) Decreases C) No change ( B ) 31) An SCR is a - - - switch A) Uni-directional B) Bi-directional C) None of the above ( A ) 32) A Triac is a - - - power switch A) Uni-directional B) Bi-directional C) None of the above ( B ) 33) A Triac has - - - terminals A) One B) Two C) Three ( C ) 34) A UJT has - - - PN Junction A) One B) Two C) Three ( A ) 35) A Diac is an - - - switch A) AC B) DC C) Both the above ( A ) 36) ICs are generally made of - - - A) Silicon B) Germanium C) None of the above ( A ) 37) Binary means - - - Binary numbers have a base of 2 A) One B) Two C) Three ( B ) 38) The digits used in a binary number system are A) 0 & 0 B) 0 & 1 C) 1 & 1 ( B ) 39) A Byte is a string of - - - Bits A) 16 B) 8 C) 2 ( B ) 40) A typical Microcomputer have - - - registers in memory A) 4096 B) 2048 C) 65536 ( C ) 41) A Gate is a logic circuit with one or more inputs, but only - - - output A) One B) Two C) Three ( A ) 42) The - - - gate has one or more high inputs, produces high output A) NOT B) OR C) XOR ( B ) 43) Which is the logic gate, where all input signals must be high to get a high output A) AND B) OR C) NOT ( A ) 44) In a NOR gate all inputs must be - - - to get high output A) Low B) High C) None of the above ( A ) 45) A NAND gate is equivalent to an - - - gate followed by an inverter A) AND B) OR C) NOR ( A ) 46) What is ISDN? A) Integrated Services Data Network. ( D ) B) Internal services digital network. C) International services data networks. D) Integrated services digital network 47) For making outgoing calls, what is the tone heard when the telephone handset is lifted A) Busy tone B) Dial tone C) No tone D) Ring back tone ( B ) 48) What is the break down voltage suggested for lightening dischargers (LD) in the MDF of telephone exchanges A)230 V B)160 V C)300 V D)1600 V ( A ) 49) What is the basic function of a telephone exchange? A)Signaling B) Switching C) Control D) All the above ( D ) 50) What is the control system used in Electronic exchange A) Stored program control B) Wire logic control ( A ) C) Electromagnetic control D) None of the above 51) The maximum number of subscriber lines in C-DOT 128P RAX type exchange is A)104 B) 112 C)96 D)88 ( D ) 52) The duplication system employed for the PSU card of an electronic exchange is A)Passive standby B)Load sharing standby C)N+1 Redundancy ( B ) D)None of the above 53) is the object of earthing for telecommunication equipment A) to provide a return earth B) To provide safety against shack to the working person ( D ) C) to provide protection against unduly high voltages D) all the above 54) What is the earth electrode called ( C ) A) A wire buried in to the earth nearby the equipment B) An iron rod buried I to the earth near the equipment C) A metal plate electrically connected to the general mass of the earth D None of the above 55) What is the maximum limit of earth resistance for Telecom equipment A) 10 ohms B) 5 ohms C) 2 ohms D) 1 ohm ( D ) 56) How the telecom equipment is connected to the earth electrode ( A ) A) by using earthing lead B) by keeping the equipment close to the electrode C) by using capacitors D) None of the above 57) What are the materials used to prepare an efficient earth for telecom equipment ( A ) A) coke, crushed coal and common salt B) plastic waste, thermo coal and glass pieces C) wood saw dust, white cement and asbestos powder D) wax, petroleum jelly and castor oil 58) In Microwave station which lead of the charger is earthed A) negative B) positive C) None of the above ( B ) 59) The maximum number of way stations can be in a control section using 2- digit code are A) 60 B) 99 C) 100 D) 90 ( B ) 60) DTMF control equipment works on A) 24 Volts B) 12 Volts C) 48 Volts D) 230 Volts ( B ) 61) Nominal ringing period at way station is A) 4 seconds B) 8 seconds C) 12 seconds D) 1 minute ( A ) 62) No. of 20 watts loud speakers permitted to connect an 250 watt amplifierare ( C ) A ) 5 B) 15 C) 12 D) 20 63) Block circuits in RE area works on ( C ) A) MW patch B) VF quad C) PET quad D) Carrier quad 64) To increase the ampere hour capacity of secondary cells, the cells are to be connected in A) Series B) Parallel C) Series and Parallel D) One above the othe ( B ) 65) No. of cable pairs required for 4 wire E&M working are ( C ) A) One B) Four C) Three D) Six 66) Duplexer is used for ( D ) A To couple two different antennaes B) To prevent interference between two antennas C) To increase the speed of transmission D) To allow one antenna to be used for reception and transmission 67) Inverter convert ( B ) A) AC to DC B) DC to AC C) DC to DC D) AC to AC 68) For converting 2 wire to 4 wire the following is required ( C ) A) Low pass filter B) High Pass filter C) Hybrid D) All these 69) In EC socket the transformer used have the impedance ratio ( D ) A) 2:1 B) 1120 : 1120 C) 470 : 1120 D) 1120 : 600 70) In a hybrid transformer the loss is ( B ) A) 2 db B) 3db C) 4 db D) No loss 71) A power amplifier gives a gain of 3 db when the input is 1 W the output is: ( B ) A) 1.3W B) 2 W C) 3 W D) .3 W 72) Grid antenna is used in ( C ) A) MW B) VHF C) UHF D) HF 73) Hybrid transformer is used in the following electronic exchange card ( D ) A) LCC B) SPC C) TIC D) TGT 74) In electronic exchange the system software is written as ( D ) A) E PROM B) E2 PROM C) RAM D) ROM 75) Which of the electronic exchange card is not redundant. ( B ) A) X SC B) LCC C) PSU D) RGD 76) The processor used in a C DOT exchange is ( A ) A) 65 CO2 B) 8085 C) Z80 D) 8031 77) Control card used in C DOT exchange is ( D ) A) SPC B) TIC C) RCT D) All the above. 78) RE repeater are spaced at every ( B ) A) 17 KM B) 40 KM C) 60 KM D) 1860 M 79) The insertion loss of way station control telephone is ( C ) A) 3 db B) 2 db C) 0.2 db D) 0.5 db. 80) The charectristic impedance of PET quad pair is -------------- ( B ) A) 600 Ohms B) 470 Ohms C) 1120 Ohms 81) The loading coil section in RE cable is ( A ) A) 915 m B) 1830 m C) 530m 82) Which of the MW frequency spectrum is used for Railway administration trunks ( B ) A) 4125 4425 MHz B) 7125 7425 MHz C) 1200 1600 MHz 83) The size of RE cable having 2 PET and 12 VF quad is represented as ( C ) A) 2 + 0 + 12 B) 0 + 2 + 12 C) 0 + 12 + 2 D) 0 + 14 84) Float charge voltae adjusted per cell in ( A ) A) 2.16 V B) 2.4 V C) 1.8 V 85) Beta in grounded emitter circuit is very high due to ( B ) A) base current is equal to collector current B) base current in small compared to collector current C) base current is higher than collector current 86) A metallic sheath is provided in RE cable to ( B ) A) to reduce cross-talk B) to reduce induce voltage C) to reduce weight of the cable 87) In RE cable the insulation resistance will be ( C ) A) less than 10 mega ohms B) more than 10 mega ohms C) above 20 mega ohms 88) Loud Speakers are always connected in parallel on ( C ) A) Voltage Matching B) Impedance Matching C) Both of them D) None of them

INDIAN RAILWAY QUESTION BANK FOR SIGNAL AND TELECOMMUNICATION