Explore topic-wise MCQs in Engineering.

In TV transmitter some possible advantages of IF modulation are

1. The modulator section and visual exciter can be solid state devices
2. VSB filter can be introduced at low power level
3. The subsequent stages following VSB filter can be tuned permanently for wideband linear operation
4. It is economical

A source is radiating power equally in all directions. If source power is P, the power density at distance d is

As compared to AM, FM requires

Capture effect occurs in

The power consumption of a present day colour TV receiver is about

Consider the following differences between QPSK and MSK

1. The side lobes in MSK are relatively much smaller in comparison to the main lobe
2. The spectrum of MSK has a main centre lobe which is 1.5 times as wide as the main lobe of QPSK
3. The waveforms of both MSK and QPSK exhibit phase continuity

As per Hartley law

In tape recorders the hissing noise is due to irregularities in magnetic coating on tape.

Waves travel on each of the line configurations in figure. In which case would the radiation be maximum

The speeds used in recording audio programs in house hold recorders are

Assertion (A): In AM carrier component remains constant in amplitude and frequency.

Reason (R): In AM the two side bands are images of each other.

The main advantage of TDM over FDM is

In FM reception, amplitude disturbances due to static change

A broadcast radio transmitter radiates 5 kW when the modulation percentage is 60. How much of this is carrier power?

For a resistance of about 15 kΩ operating in a frequency range of a few MHz, the noise voltage is in the range of

In a 50 cm TV tube, a path difference of 2 km between direct wave and interfering wave would mean a displacement between main image and ghost image equal to

In a colour TV receiver, the sound intercarrier IF is generated in

In a pulsed RADAR, the transmitter is connected to the antenna

In a colour TV receiver, PAL Dematrix consists of

In a CD, the depth and width of each pit is

A monostable multivibrator is used to generate PWM because it can

Which of the following is not necessarily the advantage of SSB over double sideband, full carrier AM?

Consider the following statements in amplitude modulation

1. The harmonic and intermodulation distortion may occur in audio and RF amplifiers
2. The sum and difference frequencies are present in the output of mixer
3. The diode detector has audio frequencies in its output
4. A balanced modulator cannot produce an AM with suppressed carrier

A resistor R is in parallel with capacitance C. The rms noise voltage of resistor in the equivalent circuit can be written as

Assertion (A): In angle modulation the transmitted amplitude is constant.

Reason (R): Angle modulation has good immunity to noise and interference.

On modulating a carrier of frequency f_c by an audio signal f_s, the following components has resulted:
fc, f_c + f_s and f_c - f_s
What is this type of modulation likely to be?

A signal m(t) = 5 cos 2p 100 t frequency modulates a carrier. The resulting FM signal is
10 cos {(2p 10⁵ t) + 15 sin (2p 100 t)}
The approximate bandwidth of the FM would be

Strength of space wave is not dependent on distance.

A 1000 kHz carrier is simultaneously modulated with 300 Hz, 800 Hz and 2 kHz audio sine waves. The frequencies present in the output will be

Which wave is also called surface wave?

ADM stands for

Which of the following is correct (FDM means Frequency Division Multiplexing and TDM means Time Division Multiplexing)?

The maximum permissible distance between two samples of a 10 kHz signal

Consider the following applications/ advantages of radar beacons

1. navigation
2. target identification
3. accurate tracking of enemy targets
4. large increase in maximum range

Some possible functions of AGC in a TV receiver are

1. To increase gain for weak signals
2. To decrease gain for strong signals
3. To change the contrast when we switch from one channel to other
4. To reduce flutter

In a certain '12 channel TDM' system it is found that channel no. 3 and channel no. 8 are connected to the same input signal. This technique

The signal plate of vidicon tube is coated with tin oxide.

In telephone systems, load is expressed in the unit of

Which of the following can be used to convert PPM into PWM?

Assertion (A): In FM all power amplifiers can be operated in class C

Reason (R): FM is a constant amplitude modulation system.

In radar system which of the following is called A scope

In a CD the channel separation is

The unit for luminous energy is

The IF bandwidth of a radar receiver is inversely proportional to

In VHS format diameter of head drum is about

While AM has __________ frequencies, FM has __________ number of sidebands.

The correct sequence of subsystem in an FM receiver is

The primary colours are

A wave is frequency modulated with an index of 0.1 and its frequency is multiplied by 8 times, the modulation index is

Short circuited stubs are preferred to O.C stubs because