1. Which of the following statements is not true for modulation?
a) it allows the use of practicable antennas.
b) It ensures transmission over long distances.
c) It reduces the bandwidth.
d) It separates different transmissions.
ans. c
2. Which of the following is not an advantage of SSB over double-side band full carrier?
a) Noise in the signal is less.
b) More channel space is available
c) Less power is required for the same signal strength.
d) None of these
ans. d
3. A modulator is a system to
a) Separate two frequencies
b) Impress the information on to a radio frequency carrier .
c) extract information form the carrier.
d) amplify the audio frequency signal.
ans. b
4. In a demodulator of a typical superhet broadcast receiver (medium and short-wave), the frequency of the input will be approximately
a) 10 MHz
b) 10 KHz
c) 500 KHz
d) 1000 Hz
ans. c
5. In AM transmission, the frequency which is not transmitted is
a) Upper side frequency
b) lower side frequency
c) audio frequency
d) carrier frequency
ans. c
6. The AM broadcast band is given by
a) 10 KHz to 30 KHz
b) 500 KHz to 1500 KHz
c) 3 to 30 MHz
d) 30 to 300 MHz
ans. b
7. In an AM wave with 100% modulation , the carrier is suppressed. The percentage of power saving will be
a) 100%
b) 50 %
c) 25 %
d) 66.7%
ans. d
8. A 400-W carrier AM modulated to a depth of 75%. The total power of the modulated wave would be
a) 210 W
b) 512 W
c) 450 W
d) 620 W
ans. b
9. The antenna current of an AM transmitter is 8 A when only carrier is sent, but is increases to 8.93 A when the carrier is modulated. The modulation of the wave is
a) 43 %
b) 57 %
c) 70.7 %
d) 100 %
ans. c
10. In high-power AM transmission, modulation is done at
a) buffer stage
b) RF power stage
c) oscillator stage
d) IF stage
ans. b
a) it allows the use of practicable antennas.
b) It ensures transmission over long distances.
c) It reduces the bandwidth.
d) It separates different transmissions.
ans. c
2. Which of the following is not an advantage of SSB over double-side band full carrier?
a) Noise in the signal is less.
b) More channel space is available
c) Less power is required for the same signal strength.
d) None of these
ans. d
3. A modulator is a system to
a) Separate two frequencies
b) Impress the information on to a radio frequency carrier .
c) extract information form the carrier.
d) amplify the audio frequency signal.
ans. b
4. In a demodulator of a typical superhet broadcast receiver (medium and short-wave), the frequency of the input will be approximately
a) 10 MHz
b) 10 KHz
c) 500 KHz
d) 1000 Hz
ans. c
5. In AM transmission, the frequency which is not transmitted is
a) Upper side frequency
b) lower side frequency
c) audio frequency
d) carrier frequency
ans. c
6. The AM broadcast band is given by
a) 10 KHz to 30 KHz
b) 500 KHz to 1500 KHz
c) 3 to 30 MHz
d) 30 to 300 MHz
ans. b
7. In an AM wave with 100% modulation , the carrier is suppressed. The percentage of power saving will be
a) 100%
b) 50 %
c) 25 %
d) 66.7%
ans. d
8. A 400-W carrier AM modulated to a depth of 75%. The total power of the modulated wave would be
a) 210 W
b) 512 W
c) 450 W
d) 620 W
ans. b
9. The antenna current of an AM transmitter is 8 A when only carrier is sent, but is increases to 8.93 A when the carrier is modulated. The modulation of the wave is
a) 43 %
b) 57 %
c) 70.7 %
d) 100 %
ans. c
10. In high-power AM transmission, modulation is done at
a) buffer stage
b) RF power stage
c) oscillator stage
d) IF stage
ans. b
