Communication Systems — Part 2 MCQs with Explanations

0.5 kW is the correct answer to “The maximum power output of a standard A earth station over the total band allocated to satellite communication is about”. This question is standard in competitive examination syllabi for Communication Systems.

FSK is the correct answer to “For telegraphy the most commonly used modulation system is”. This question is standard in competitive examination syllabi for Communication Systems.

Produce 100% modulation is the correct answer to “The main function of a balanced modulator is to”. This question is standard in competitive examination syllabi for Communication Systems.

Amplitude of distant sidebands increases is the correct answer to “In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then”. This question is standard in competitive examination syllabi for Communication Systems.

True is the correct answer to “Full duplex operation permits transmission in both directions at the same time.”. This question is standard in competitive examination syllabi for Communication Systems.

Reflected colour for opaque object and wavelength transmitted through it for transparent objects is the correct answer to “The colour of an object is decided by”. This question is standard in competitive examination syllabi for Communication Systems.

PSK is the correct answer to “Which of the following is a digital modulation technique”. This question is standard in competitive examination syllabi for Communication Systems.

Both A and R are correct but R is not correct explanation of A is the correct answer to “Assertion (A): In FM the frequency of the carrier is varied by the modulating voltage Reason (R): FM and PM are two forms of angle modulation.”. This question is standard in competitive examination syllabi for Communication Systems.

Pulse Amplitude Modulation is the correct answer to “PAM stands for”. This question is standard in competitive examination syllabi for Communication Systems.

Stepped index operation is the correct answer to “Which of the following does not cause losses in optical fibre cables”. This question is standard in competitive examination syllabi for Communication Systems.

Eliminates any change in amplitude of received FM signals is the correct answer to “In a FM receiver, amplitude limiter”. This question is standard in competitive examination syllabi for Communication Systems.

The radiation at right angles is zero is the correct answer to “When the length of antenna is a whole wavelength”. This question is standard in competitive examination syllabi for Communication Systems.

FM only is the correct answer to “Under ordinary circumstances, impulse noise can be reduced in”. This question is standard in competitive examination syllabi for Communication Systems.

Monostable multi-vibrator is the correct answer to “Which of the following is used to generate PDM”. This question is standard in competitive examination syllabi for Communication Systems.

Statistically independent is the correct answer to “A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be”. This question is standard in competitive examination syllabi for Communication Systems.

15 is the correct answer to “A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is”. This question is standard in competitive examination syllabi for Communication Systems.

Linear devices is the correct answer to “For a low level AM system, the amplifiers modulated stage must be”. This question is standard in competitive examination syllabi for Communication Systems.

Linear devices is the correct answer to “In case of low level amplitude modulation system, the amplifiers following the modulated stage must be”. This question is standard in competitive examination syllabi for Communication Systems.

75 kHz is the correct answer to “Commercial Frequency deviation of FM is”. This question is standard in competitive examination syllabi for Communication Systems.

113 is the correct answer to “An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.”. This question is standard in competitive examination syllabi for Communication Systems.

Noise power produced in the system is proportional to bandwidth is the correct answer to “In any system, excessive bandwidth is avoided because:”. This question is standard in competitive examination syllabi for Communication Systems.

24 MHz is the correct answer to “A communication receiver has an intermediate frequency of 9 MHz. What is the frequency of its oscillator when it is tuned to 15 MHz”. This question is standard in competitive examination syllabi for Communication Systems.

x(t) is a DSB-SC signal is the correct answer to “Which one of the statements regarding the following signal x(t) = 5sin(2π × 10 3 t)sin(2π × 10 6 t) is incorrect”. This question is standard in competitive examination syllabi for Communication Systems.

1000 + 20cos(2π100t) is the correct answer to “The narrow band FM signal is 10cos(2π1000t + 0.2sin(2π100t)) what is instantaneous frequency:”. This question is standard in competitive examination syllabi for Communication Systems.

a-5, b-3, c-2, d-1 is the correct answer to “Match List-I with List-II and select the correct answer using the options given below: List-I List-II a. Resistance 1. Current Noise b. Diode 2. Partition Noise c. Triode 3. Shot Noise d. p-n junction Noise 4. Atmospheric 5. Johnson Noise”. This question is standard in competitive examination syllabi for Communication Systems.

More power to transmit same signal is the correct answer to “The advantages of DSB over SSB full carrier AM is”. This question is standard in competitive examination syllabi for Communication Systems.

Increase the transmission capacity is the correct answer to “Modems are used for data transmission telephone lines to”. This question is standard in competitive examination syllabi for Communication Systems.

image frequency problem is the correct answer to “Super heterodyne radio receiver suffers from-”. This question is standard in competitive examination syllabi for Communication Systems.

525 Hz is the correct answer to “In the FM wave described by equation v = 15sin(4 × 10 8 t + 3sin1100t), the maximum frequency deviation is”. This question is standard in competitive examination syllabi for Communication Systems.

$$\int\limits_{ - \infty }^\infty {{f_x}\left( x \right)dx = 1} $$ is the correct answer to “Probability density function of random variable x is:”. This question is standard in competitive examination syllabi for Communication Systems.

R(τ) = B × N0 sin c(2Bτ) is the correct answer to “The auto-correlation function of a band limited (B) white noise process is given by”. This question is standard in competitive examination syllabi for Communication Systems.

Triangular over the range -2a to 2a is the correct answer to “The outputs of two noise sources each producing uniformly distributed noise over the range -a to +a are added. What is the p.d.f. of the added noise”. This question is standard in competitive examination syllabi for Communication Systems.

frequency deviations are converted into voltage variations is the correct answer to “In a FM demodulator,”. This question is standard in competitive examination syllabi for Communication Systems.

$$\frac{{6K}}{{9 + {\omega ^2}}}$$ is the correct answer to “The power spectral density of the stationary noise process N(t) having auto correlation R uu (τ) = Ke -3|τ| is”. This question is standard in competitive examination syllabi for Communication Systems.

$$F = \frac{{\frac{{{S_i}}}{{{N_i}}}}}{{\frac{{{S_0}}}{{{N_0}}}}}$$ is the correct answer to “Noise figure is defined as”. This question is standard in competitive examination syllabi for Communication Systems.

a-2, b-4, c-1, d-3 is the correct answer to “The List-I and the list-II . Match the attribute to the modulation system that best meets it. List-I (lists the attributes) List-II (lists of the modulation systems) a. Power efficient transmission of signals 1. Conventions AM b. Most bandwidth efficient transmission of voice signals 2. FM c. Simplest receiver structure 3. VSB d. Bandwidth efficient transmission of signals with significant dc component 4. SSB-SC”. This question is standard in competitive examination syllabi for Communication Systems.

Limiter is the correct answer to “Noise in FM receiver is reduced by”. This question is standard in competitive examination syllabi for Communication Systems.

Coherent detector is the correct answer to “The most common detector used in an AM radio broadcast receiver is:”. This question is standard in competitive examination syllabi for Communication Systems.

5 is the correct answer to “A random process obeys Poisson's distribution. It is given that the mean of the process is 5. Then the variance of the process is”. This question is standard in competitive examination syllabi for Communication Systems.

790 kHz is the correct answer to “For an AM signal, the bandwidth is 20 kHz and the highest frequency component present is 800 kHz. The carrier frequency used for this AM signal is”. This question is standard in competitive examination syllabi for Communication Systems.