Gibilisco - Wireless Transmitters And Receivers
- 1.A radio wave has a frequency of 1.55 MHz. The highest modulating frequency that can beused effectively is about
- A.
1.55 kHz.
- B.
15.5 kHz.
- C.
155 kHz.
- D.
1.55 MHz.
- 2.The reflected wave
- A.
Arrives in phase with the direct wave.
- B.
Arrives out of phase with the direct wave.
- C.
Arrives in a variable phase compared with the direct wave.
- D.
Is always horizontally polarized.
- 3.An advantage of FSK over on/off keying is the fact that FSK
- A.
Offers better frequency stability.
- B.
Can provide faster data rates.
- C.
Reduces the number of receiving errors.
- D.
Forget it! On-off keying is just as good as FSK.
- 4.The highest layer of the ionosphere is
- A.
The D layer.
- B.
The E layer.
- C.
The F layer.
- D.
None of the above.
- 5.If an AM signal is modulated with audio having frequencies up to 5 kHz, then what is thecomplete signal bandwidth?
- A.
10 kHz
- B.
20 kHz
- C.
50 kHz
- D.
500 kHz
- 6.An LSB, suppressed-carrier signal can be demodulated by
- A.
An envelope detector.
- B.
A diode.
- C.
A ratio detector.
- D.
A product detector.
- 7.Which of the following modes is used to send image data over telephone lines?
- A.
On/off keying
- B.
Fax
- C.
AM
- D.
Product detection
- 8.The S/N ratio is a measure of
- A.
The sensitivity of a receiver.
- B.
The selectivity of a receiver.
- C.
The dynamic range of a receiver.
- D.
The efficiency of a transmitter.
- 9.Suppose an SSB suppressed carrier is at 14.335 MHz, and audio data is contained in a bandfrom 14.335 to 14.338 MHz. What is this mode?
- A.
DSB
- B.
LSB
- C.
USB
- D.
AFSK
- 10.A receiver that responds to a desired signal, but not to another signal very close by infrequency, has good
- A.
Sensitivity.
- B.
Noise figure.
- C.
Dynamic range.
- D.
Selectivity.
- 11.Fill in the blank in the following sentence to make it true: “The deviation of a narrowbandvoice FM signal normally extends up to either side of the unmodulated-carrier frequency.”
- A.
3 kHz
- B.
5 kHz
- C.
10 kHz
- D.
3 MHz
- 12.An FM detector with built-in limiting is
- A.
A ratio detector.
- B.
A discriminator.
- C.
An envelope detector.
- D.
A product detector.
- 13.In which mode of PM does the peak power level of the pulses vary?
- A.
PAM
- B.
PDM
- C.
PIM
- D.
PFM
- 14.A continuously variable signal (such as music audio) can be recovered from a signal havingonly a few discrete levels or states by means of
- A.
A ratio detector.
- B.
A D/A converter.
- C.
A product detector.
- D.
An envelope detector.
- 15.In which mode are signals intertwined in the time domain at the transmitter, and thenseparated again at the receiver?
- A.
FDM
- B.
AFSK
- C.
PCM
- D.
None of the above
- 16.Which of the following modes can be demodulated with an envelope detector?
- A.
AM
- B.
CW
- C.
FSK
- D.
USB
- 17.The bandwidth of a fax signal is kept narrow by
- A.
Sending the data at a slow rate of speed.
- B.
Maximizing the number of digital states.
- C.
Optimizing the range of colors sent.
- D.
Using pulse modulation.
- 18.The dynamic range in a superhet is largely influenced by the performance of the
- A.
Local oscillator.
- B.
Product detector.
- C.
Front end.
- D.
Selectivity in the IF chain.
- 19.Frequency sweeping can be used to get a transmitter to produce
- A.
Spread-spectrum signals.
- B.
Time division multiplexed signals.
- C.
Narrowband AM signals.
- D.
Double sideband, suppressed carrier signals.
- 20.Fill in the blank to make the following sentence true: “The reception of can beimproved by the use of DSP.”
- A.
SSB signals
- B.
SSTV signals
- C.
Synchronized communications signals
- D.
Any of the above
Questions: 30 | Attempts: 5169 | Last updated: Nov 9, 2020
-
Sample QuestionWhich area of the world first deployed cellular services for commercial use?
Questions: 10 | Attempts: 1779 | Last updated: Apr 1, 2020
-
Sample QuestionThis is the family of specifications for wireless local area networks (WLANs) developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE).
Questions: 10 | Attempts: 1233 | Last updated: Jan 9, 2019
-
Sample QuestionWhat can be done to fix a hidden node issue? (Choose all that apply)
Back to top