1. Modulation is primarily accomplished to ?

Produce side bands

Mix two-waves of different frequencies

Improve transmission efficiency

Transmit audio-frequency signal over long distance

Answer: Transmit audio-frequency signal over long distance

Explanation:


2. If modulation index is 0.8 then what will be the transmission power efficiency for a tone modulated signal ?

24.24%

11.11%

33.33%

21.95%

Answer: 24.24%

Explanation:


3. Percentage modulation of an AM wave having a power content of 8 KW at carrier frequency and 2 KW in each of its side bands is: ?

60%

70%

100%

80%

Answer: 100%

Explanation:


4. A 1 kW carrier is Amplitude Modulated to a depth of 60%. The total power in the modulated carrier is ?

1 kW

1.06 kW

1.6 kW

1.18 kW

Answer: 1.18 kW

Explanation:


5. A carrier is modulated by two modulating waves A and B having modulation index of 0.6 and 0.8 respectively. The overall modulation index is ?

1.0

0.7

0.2

1.4

Answer: 1.0

Explanation:


6. An AM signal with a carrier of 6KW produces a modulation of 100% what will be the power produced in each side band ?

1KW

0.15KW

15KW

1.5KW

Answer: 1.5KW

Explanation:


7. The modulation index of an amplitude modulated wave is changed from 0 to 1. The transmitted power is ?

Doubled

Halved

Increased by 50 percent

unchanged

Answer: Increased by 50 percent

Explanation:


8. In amplitude modulated system if the total power is 600W and the power in the carrier is 400W, the modulation index ?

0.5

0.75

0.9

1

Answer: 1

Explanation:


9. The ratio of modulating power to total power at 100% modulation will be ?

2:3

3:1

1:3

3:2

Answer: 1:3

Explanation:


10. Before transmission message signal is modulated with carrier signal for : ?

Decreasing the height of transmitting antenna

Increasing the amplitude of message signal

Decreasing the amplitude of message signal

Increasing the height of transmitting antenna

Answer: Decreasing the height of transmitting antenna

Explanation: