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Electronics Engineering Objective Questions { Analog Communication System }



134. In frequency modulation for a given frequency deviation, the modulation index varies
A. inversely as the modulating frequency
B. directly as the modulating frequency
C. independent of modulating frequency
D. none of the above
Discussion
135. In case the depth of modulation is doubled in F.M. system, the power transmitted
A. increase byfactor of
B. increase by factor of 13
C. increase by factor of 2
D. none of the above
Discussion
136. In an FM signal, the power
A. increases as modulation index increases
B. reduces as modulation index increases
C. remains constant even when modulation index varies
D. none of the above
Discussion
137. Which of the following oscillator is not in FM?
A. Crystal oscillator (b) Hartley oscillator
B. Colpitts oscillator
C. All of the above
D.
Discussion
138. Which of the following statement about FM is false?
A. The loudest sound produces maximum frequency deviation
B. The audio modulating frequency determines the rate of frequency swing
C. A FM signal with a modulation index Mr is passed through a frequency tripper. The modulation index of the output of the tripler will be
D. None of the above
Discussion
139. FM and AM transmitters are to be compared. Which of the following statement is valid?
A. AM transmitter is more efficient as compared to FM transmitter
B. FM transmitter is more efficient as compared to AM transmitter
C. FM and AM transmitters have the same efficiency
D. Efficiency of transmitters depends on frequency only
Discussion
140. An FM signal with a deviation a is passed through a mixer, and has its frequency reduced six fold. The deviation in the output of the mixer will be
A. 6 a
B. 4a
C. a
D. indeterminate
Discussion

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