1. Modulation is used to a. increase the carrier power b. reduce the bandwidth usedc. allow the use of practical antennasd. shorten the transmission channel2. Modulation is done at a. the transmitterb. the receiverc. the channel d. the antenna3. In an AM wave, useful power is carried by a. the sidebandsb. the carrier c. both d. either4. Which of these could not be used to remove the unwanted sideband in SSB? a. Filter Methodb. Phase Shift Method c. Third Methodd. Balanced Modulator5. In amplitude modulation, the ____________ of the carrier is varied according to the strength of the signal.a. amplitudeb. phase c. frequency d. period6. The output of a balanced modulator is a. USB and LSBb. LSBc. USBd. carrier7. A 900 kHz carrier is amplitude modulated with 4000 Hz audio tone. The lower and upper sideband frequencies are a. 450 and 1800 kHzb. 800 and 1000 kHzc.896 and 904 kHzd. 4000 and 8000 kHz8. The HF band covers the frequency range a. 3 30 MHz b. 30 300 MHzc. 30 300 kHzd. 300 kHz 3 MHz9. In amplitude modulation, if the peak signal is 0.5 volt and the carrier peak is 1 volt, the depth of modulation is a. 25%b. 50%c. 75%d. 78.5%10. In a communications system, noise is most likely to affect the signal at the a. transmitterb. channelc. information sourced. destination11. Another term for Amplitude Modulation a. DSBSCb. SSBSCc. DSBFCd. SSBFC

12. The bandwidth of an AM transmitter if the carrier frequency is 1000 kHz and the modulation frequency varies from 1 kHz to 10 kHz is a. 2000 kHzb. 2 kHzc. 20 kHzd. 20.1 kHz

13. If the modulation index of an AM wave is increased from 0 to 1, the transmitter power will be a. unchanged b. increased by 50% c. increased by 100%d. decreased by 50% 14. When the modulation index of an AM amplifier is 1, the amplitude of the carrier is ____________ the amplitude of the modulating signal. a. greater than b. equal to c. less thand. double15. Overmodulation results in ____________. a. weakening of the signal b. excessive carrier powerc. distortiond. either a or b 16. If the modulation index of an AM amplifier is 0.80, the % modulation is equal to a. 20%b. 80%c. 0.80d. 0.20

17. Both frequency and phase modulation utilize ____________ modulation. a. phase b. amplitudec. digitald. angle18. The maximum percentage modulation without distortion in an amplitude modulation system is a. 20%b. 50%c. 110%d. 100%

19. A form of AM in which the carrier is transmitted at full power, but only one of the sidebands is transmitted. a. SSBFCb. SSBSCc. DSBFCd. DSBSC20. Emission with only one sideband transmission a. A3E b. J3Ec. 11BEd. H3E