1. The theory of radio waves was originated by:
a. | Marconi | c. | Maxwell |
b. | Bell | d. | Hertz |
ANS: C
2. The person who sent the first radio signal across the Atlantic ocean was:
a. | Marconi | c. | Maxwell |
b. | Bell | d. | Hertz |
ANS: A
3. The transmission of radio waves was first done by:
a. | Marconi | c. | Maxwell |
b. | Bell | d. | Hertz |
ANS: D
4. A complete communication system must include:
a. | a transmitter and receiver |
b. | a transmitter, a receiver, and a channel |
c. | a transmitter, a receiver, and a spectrum analyzer |
d. | a multiplexer, a demultiplexer, and a channel |
ANS: B
5. Radians per second is equal to:
a. | 2p ´ f | c. | the phase angle |
b. | f ¸ 2p | d. | none of the above |
ANS: A
6. The bandwidth required for a modulated carrier depends on:
a. | the carrier frequency | c. | the signal-plus-noise to noise ratio |
b. | the signal-to-noise ratio | d. | the baseband frequency range |
ANS: D
7. When two or more signals share a common channel, it is called:
a. | sub-channeling | c. | SINAD |
b. | signal switching | d. | multiplexing |
ANS: D
8. TDM stands for:
a. | Time-Division Multiplexing | c. | Time Domain Measurement |
b. | Two-level Digital Modulation | d. | none of the above |
ANS: A
9. FDM stands for:
a. | Fast Digital Modulation | c. | Frequency-Division Multiplexing |
b. | Frequency Domain Measurement | d. | none of the above |
ANS: C
10. The wavelength of a radio signal is:
a. | equal to f ¸ c |
b. | equal to c ¸ l |
c. | the distance a wave travels in one period |
d. | how far the signal can travel without distortion |
ANS: C
11. Distortion is caused by:
a. | creation of harmonics of baseband frequencies |
b. | baseband frequencies "mixing" with each other |
c. | shift in phase relationships between baseband frequencies |
d. | all of the above |
ANS: D
12. The collection of sinusoidal frequencies present in a modulated carrier is called its:
a. | frequency-domain representation | c. | spectrum |
b. | Fourier series | d. | all of the above |
ANS: D
13. The baseband bandwidth for a voice-grade (telephone) signal is:
a. | approximately 3 kHz | c. | at least 5 kHz |
b. | 20 Hz to 15,000 Hz | d. | none of the above |
ANS: A
14. Noise in a communication system originates in:
a. | the sender | c. | the channel |
b. | the receiver | d. | all of the above |
ANS: D
15. "Man-made" noise can come from:
a. | equipment that sparks | c. | static |
b. | temperature | d. | all of the above |
ANS: A
16. Thermal noise is generated in:
a. | transistors and diodes | c. | copper wire |
b. | resistors | d. | all of the above |
ANS: D
17. Shot noise is generated in:
a. | transistors and diodes | c. | copper wire |
b. | resistors | d. | none of the above |
ANS: A
18. The power density of "flicker" noise is:
a. | the same at all frequencies | c. | greater at low frequencies |
b. | greater at high frequencies | d. | the same as "white" noise |
ANS: C
19. So called "1/f" noise is also called:
a. | random noise | c. | white noise |
b. | pink noise | d. | partition noise |
ANS: B
20. "Pink" noise has:
a. | equal power per Hertz | c. | constant power |
b. | equal power per octave | d. | none of the above |
ANS: B
21. When two noise voltages, V1 and V2, are combined, the total voltage VT is:
a. | VT = sqrt(V1 ´ V1 + V2 ´ V2) | c. | VT = sqrt(V1 ´ V2) |
b. | VT = (V1 + V2)/2 | d. | VT = V1 + V2 |
ANS: A
22. Signal-to-Noise ratio is calculated as:
a. | signal voltage divided by noise voltage |
b. | signal power divided by noise power |
c. | first add the signal power to the noise power, then divide by noise power |
d. | none of the above |
ANS: B
23. SINAD is calculated as:
a. | signal voltage divided by noise voltage |
b. | signal power divided by noise power |
c. | first add the signal power to the noise power, then divide by noise power |
d. | none of the above |
ANS: D
24. Noise Figure is a measure of:
a. | how much noise is in a communications system |
b. | how much noise is in the channel |
c. | how much noise an amplifier adds to a signal |
d. | signal-to-noise ratio in dB |
ANS: C
25. The part, or parts, of a sinusoidal carrier that can be modulated are:
a. | its amplitude | c. | its amplitude, frequency, and direction |
b. | its amplitude and frequency | d. | its amplitude, frequency, and phase angle |
ANS: D
No comments:
Post a Comment