Q.1
Assertion (A): In FM the frequency of the carrier is varied by the modulating voltageReason (R): FM and PM are two forms of angle modulation.
  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is correct but R is wrong
  • A is wrong but R is correct
Q.2
Full duplex operation permits transmission in both directions at the same time.
  • True
  • False
Q.3
In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
  • Amplitude of distant sidebands decreases
  • Amplitude of distant sidebands increases
  • Amplitude of distant sidebands remains constant
  • Amplitude of distant sidebands first increases, then decreases
Q.4
The modulation index of an FM is changed from 0 toHow does the transmitted power change?
  • Gets halved
  • Gets doubled
  • Gets increased by 50 percent
  • Remains unchanged
Q.5
For a given carrier wave, maximum undistorted power is transmitted when value of modulation is
  • 1
  • 0.8
  • 0.5
  • 0
Q.6
In TV systems, equalising pulses are sent during
  • Horizontal blanking
  • Vertical blanking
  • Serrations
  • Horizontal retrace
Q.7
For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as
  • 2E
  • 3E
  • 4E
  • 6E
Q.8
In Modulation, “carrier” is
  • Resultant wave
  • Speech voltage to be transmitted
  • Voltage with constant frequency, phase or amplitude
  • Voltage for which frequency, phase or amplitude is varied
Q.9
If in a broadcasting studio, akHz carrier is modulated by an audio signal of frequency range 100-kHz, the width of channel is __________ kHz.
  • 5
  • 4.9
  • 995
  • 10
Q.10
Which one of the following is analog?
  • PCM
  • PWM
  • Delta modulation
  • Differential PCM
Q.11
For AM receivers the standard IF frequency is
  • 106 kHz
  • 455 kHz
  • 1.07 MHz
  • 10.7 MHz
Q.12
FM transmitting and receiving equipment as compared to AM equipment is
  • Costly
  • Cheaper
  • Almost equally costly
  • None of the above
Q.13
Leak type bias is used in plate modulated class C amplifier to
  • Increase the bandwidth
  • Prevent over modulation
  • Prevent excessive grid current
  • Prevent tuned circuit damping
Q.14
Fourier analysis indicate that a square wave can be represented as
  • A fundamental sine wave and odd harmonics
  • A fundamental sine wave and even harmonics
  • A fundamental sine wave and harmonics
  • Fundamental and subharmonic sine waves
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