Discussion
Home ‣ Electronics and Communication Engineering ‣ Communication Systems Comments
- Question
Non-coherently detection is not possible for
Options- A. PSK
- B. ASK
- C. FSK
- D. both (a) and (c)
- Correct Answer
- PSK
- 1. Radio broadcasts are generally
Options- A. amplitude modulation
- B. frequency modulation
- C. both amplitude and frequency modulation
- D. neither amplitude nor frequency modulation Discuss
- 2. Push pull amplifier is
Options- A. voltage amplifier
- B. current amplifier
- C. power amplifier
- D. none of the above Discuss
- 3. If the frequency of a wave 20 Hz, the time period is
Options- A. 20 secs
- B. 2 secs
- C. 0.2 secs
- D. 0.05 secs Discuss
- 4. Assertion (A): Free space does not interfere with normal radiation and propagation of radio waves
Reason (R): Free space has no magnetic or gravitational fields.
Options- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is correct but R is wrong
- D. A is wrong but R is correct Discuss
- 5. Which of the following is the indirect way of FM generation?
Options- A. Reactance bipolar transistor modulator
- B. Armstrong modulator
- C. Varactor diode modulator
- D. Reactance FM modulator Discuss
- 6. Energy content of atmospheric noise
Options- A. does not depend on frequency
- B. decreases as frequency is increased
- C. increases as frequency is increased
- D. either (a) or (c) depending on the temperature Discuss
- 7. The range of a cordless telephone is about
Options- A. 1000 m
- B. 500 m
- C. 100 m
- D. 10 m Discuss
- 8. VSB modulation is preferred in TV because
Options- A. it reduces the bandwidth requirement to half
- B. it avoids phase distortion at low frequencies
- C. it results in better reception
- D. none of the above Discuss
- 9. Assertion (A): The phenomenon of differential mobility is called transferred electron effect.
Reason (R): GaAs exhibits transferred electron effect.
Options- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is correct but R is wrong
- D. A is wrong but R is correct Discuss
- 10. A line is excited by a 100 V dc source. If reflection coefficients at both ends are 1 each then
Options- A. there will be no oscillations on line
- B. there will be only 1 or 2 oscillations on line
- C. there will be a finite number of oscillations on line
- D. the oscillations will continue indefinitely Discuss
Communication Systems problems
Search Results
Correct Answer: frequency modulation
Explanation:
Frequency modulation gives noise free reception and is used for radio broadcasts.
Correct Answer: power amplifier
Explanation:
Push pull is a power amplifier.
Correct Answer: 0.05 secs
Explanation:
.
Correct Answer: Both A and R are correct and R is correct explanation of A
Explanation:
Since free space does not have magnetic and other fields, waves can propagate without any interference.
Correct Answer: Armstrong modulator
Explanation:
It generates FM through phase modulation.
Correct Answer: decreases as frequency is increased
Explanation:
Atmospheric noise decreases as frequency is increased.
Correct Answer: 100 m
Explanation:
The range depends on quality of instrument and is about 100 m.
Correct Answer: it reduces the bandwidth requirement to half
Explanation:
VSB (vestigial side band) transmission transmits one side band fully and the other side band partially thus, reducing the bandwidth requirement.
Correct Answer: Both A and R are correct but R is not correct explanation of A
Explanation:
A Gunn diode uses GaAs which has a negative differential mobility, i.e., a decrease in carrier velocity with increase in electric field.
This effects is called transferred electron effect. The impedance of a Gunn diode is tens of ohms.
A Gunn diode oscillator has a resonant cavity, an arrangement to couple Gunn diode to cavity, biasing arrangement for Gunn diode and arrangement to couple RF power to load.
Applications of Gunn diode oscillator include continuous wave radar, pulsed radar and microwave receivers.
Correct Answer: the oscillations will continue indefinitely
Explanation:
Because rv = 1 at each end, the line voltage will not reach a steady value and oscillations will continue indefinitely.
Comments
There are no comments.More in Electronics and Communication Engineering:
Programming
Copyright ©CuriousTab. All rights reserved.