Explore topic-wise MCQs in Engineering.

The RF section of a radio transmit generally consists of

AC hum is picked up from power cables

The circuit of figure give an output which is

The amplitude of a modulated RF aerial current is 6 A on the peaks of modulation and 4 A on the troughs of modulation. The value of carrier amplitude is

In practical commercial AM system channel bandwidth is

The currents fed to the two dipoles of turnstile antenna are

The storage capacity of audio CD is 540 Mb per side.

The device most likely to be found in an SSB transmitter is

Which of the following microphones has lowest output impedance?

In case of a low level AM transmitter, the amplifier modulated stage must be

Point out the false statement

In a low level AM system, the modulated amplifiers stage must be

In cell communication

A ground wave travels along surface of ground.

Homodyne detection means

A radio station works at 800 kHz and uses AM. If this is a public broadcast system, it should transmit using

In narrowband FM, the modulation index is

A single-sideband (SSB) signal contains 3 kW. The power content of the carrier is __________ kW.

Waves of frequencies higher than 30 MHz penetrate the atmosphere.

During fast forward operation of a tape recorder

In a superheterodyne broadcast receiver, the frequency of local oscillator is __________ the incoming signal frequency.

PCM : Quantising Noise :: Transistor :

PAL stands for

In digital TV digital imaging standard comprises

In an SSB transmitter one is most likely to find

The antenna current of an AM transmitter is 8 A. When only the carrier is sent, but it increases to 8.93 A. when the carrier is sinusoidally modulated. The percentage modulation is nearly

The 2 out of 5 code has

Which of the following modulation is analog in nature?

Consider the following statements as regards BPSK and QPSK:

1. In BPSK we deal individually with each bit of duration T_b
2. In QPSK we lump two bits to form a symbol
3. In both BPSK and QPSK signal changes occur at bit rate
4. In QPSK the symbol can have any one of four possible values

In equally tampered musical scale, an octave is divided into

Figure of merit is always unity in

In the spectrum of a FM wave

The gap width in audio heads is about 0.01 mm.

Speeds of sound and radio waves are equal.

In PCM, bit duration is defined as

Assertion (A): If frequency is high, the distance between transmitter and antenna may be an appreciable fraction of wavelength

Reason (R): Wavelength is inversely proportional to frequency.

The spectral component of noise associated with k^th frequency is given, in the limit as f 0 by n_k(t) written as n_k(t) = C_k cos (2pk ft + _k)
Consider the following statements as regards C_k and _k

1. C_k and _k are independent of one another
2. C_k and _k are independent of the amplitude of a spectral component at a different frequency
3. C_t and _k are independent of the phase of a spectral component at a different frequency

In a modulator it is found that the amplitude spectrum consists a component at f_c, the carrier frequency and one component each at f_c - f_s and f_c + f_s where f_s is the modulating signal frequency. Then the modulator used is

Troposphere is the portion of atmosphere

Earth's curvature affects the effective height of antenna.

A narrowband amplifier is one that has a passband

In PCM, the quantization noise depends on

The power density spectrum of noise voltage at the input of a network is S_ni and that at the output of the network is S_no. If transfer function of network is H( ), the corresponding noise figure is

Pulse modulation is often used in

In a colour TV receiver, the function of comb filter is

In AM the amplitude of carrier components ... while in FM it

Which of the following form of angle modulation in this? If e = 10 sin(10⁸ t + 3 sin 10⁴ t)

The noise performance of a square law demodulator of AM signal is

A communication receiver is

Which of the following microphones has bidirectional feature?