Not to worry buddy I will get the BSNL TTA Exam paper so that you can get idea from the paper and I hope you will clear it .

Here is the exam paper
(1) The most common modulation system used for telegraphy is

(a) FSK

(b) PSK.

(c) PCM

(d) single tone modulation

(e) Two tone modulation

(2)VSB is an abbreviation of vestigal sideband, is derived by filtering

(a) DSB

(b) AM

(c) either (a) or (b)

(d) PM

(3) The Hartely law states that

(a) The maximum rate of information transmission depends on the depth of modulation

(b) The maximum rate of information depends on the channel bandwidth.

(c) Only binary codes may be used

(d) Redundancy is essential

(4) The FM signal with, a modulation index mf is passed through a frequency tripler. The wave in the output of the tripler will have a modulation index of

(a) mf/9

(b) mf/3

(c) mf

(d) 3 mf

(e) 9mf

(5) In high power AM transmission, modulation is done at

(a) Buffer stage

(b) Oscillator stage

(c) RF power stage

(d) If stage

(6) Companding is used

(a) In delta modulator to combat noise

(b) To limit amplitude in PCM transmitters.

(c) In PWM for working it with TDM

(d) To protect small signals in PCM from quantizing distortion

(e) In PCM to reduce the SNR

(7) In PCM system the SNR of the output signal increases

(a) Inversely with bandwidth

(b) Exponential with bandwidth

(c) With rate of sampling

(d) At low frequencies only

(8) Armstrong modulator generates

(a) Phase modulated signal

(b) Frequency modulated signal

(c) Both of these

(d) Pulse code modulated signal

(e) AM and PCM signals

(9) A Klystron is a cavity acting as buncher and catcher is used as microwave tube for

(a) Guiding waves

(b) Velocity modulation

(c) frequency modulation

(d) impedance matching

(e) All of these

(10) Easily adjustable tuning component in a waveguide is

(a) plunger

(b) plunger and stub

(c) screw

(d) both (a) and (c)

(e) both (b) and (c)

(11) A ferrite is

(a) A non-conductor with magnetic properties

(b) A conductor with magnetic properties

(c) A semiconductors

(d) An insulator which attenuates magnetic fields

(e) A compound with good conductivity.

(12) Vacuum tubes eventually fail at microwave frequencies because of their

(a) Inter electrode capacitance

(b) Small series inductance

(c) Large shunt capacitance

(d) Short transit time

(e) Increased noise figure

(13) The biggest disadvantage the IMP ATT diode has is its

(a) Low Efficiency

(b) high noise

(c) Low BW

(d) inability to provide pulse operation

(e) low power handling ability

(14) In AM transmission the frequency, which is not transmitted is

(a) carrier frequency

(b) audio frequency

(c) upper side frequency

(d) lower side frequency

(15) FM broadcast band lies in

(a) VHF

(b) UHF

(c) SHF

(d) HF

(16) Automatic gain control is used

(a) to maintain the tuning correct

(b) to reduce the voltage of loud passage of music

(c) to maintain the same amount of output, when stations of different strength are received

(d) to increase the amplification at high frequencies

(17) The modulation system inherently is most noise resistant in

(a) SSB suppressed carrier

(b) FM

(c) PPM

(d) PCM

(18) In practical waveguide act as

(a) low pass filter

(b) high pass filter

(c)band pass filter

(d)band stop filter

(19) The antenna efficiencies achieved in practice depend upon

(a) wave length

(b) impedance

(c) frequency

(d) none of above

(20) The process of compressing the digital codes at the transmitter and then expanding them back to their original form at receiver is known as

(a) Quantizing

(b) companding

(c) step sizing

(d) modulation