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1. Why can't audio frequencies be directly transmitted through an antenna system?

a) The antenna required would be too long
b) Too much power would be required
c) The receiver would distort the information waveform
d) None of the above

2. What is the wavelength of a 1 MHz signal?

a) 100 Meters
b) 200 Meters
c) 300 Meters
d) None of the above

3. What is the wavelength of a 600 MHz signal?

a) 1 Meter
b) 0.5 Meter (50 cm)
c) 0.75 Meter
d) None of the above

4. A certain transmitter's antenna is 1/4 wavelength long and measures 29.528 inches. What is the actual operating frequency of this transmitter? (1 inch = 2.54 cm).

a) 25 MHz
b) 50 MHz
c) 100 MHz
d) None of the above

5. In troubleshooting a stage in an electronic device, where is the best place to check the power supply?

a) At the output terminal of the voltage regulator IC
b) Directly at the terminals of the device using the power
c) At the power supply buss line
d) None of the above

6. What are the steps of troubleshooting in correct order?

a) Visual inspection, Check power supply, Check inputs & outputs
b) Check power supply, Visual inspection, Check inputs & outputs
c) Visual inspection, Check inputs & outputs, Check power supply
d) None of the above

7. Why is modulation and carrier transmission necessary in radio?

a) To keep antenna lengths reasonable
b) To allow stations to be separated by radio receivers
c) Both A and B
d) None of these

8. Which of these describes demodulation?

a) Recovering information from a carrier wave
b) Placing information onto a carrier wave
c) Controlling the frequency of a carrier wave
d) None of the above

9. What type of wave is pictured in the spectrogram above?

a) Pure sine wave
b) Square wave
c) Triangle wave
d) None of the above

10. The horizontal axis of a spectrum analyzer is labeled in what units?

a) Time - Seconds
b) Resistance - Ohms
c) Frequency - Hz
d) None of the above

11. What laboratory instrument is used to view signals in the frequency domain?

a) Oscilloscope
b) Function generator
c) Spectrum analyzer
d) None of the above

12. The signal shown above is fed into a bandpass filter with a center frequency of 2 KHz. What will the output of the bandpass filter look like on an oscilloscope?

a) A 1 KHz square wave
b) A 1 KHz sine wave
c) A 2 KHz triangle wave
d) None of the above

13. What signal to noise ratio, in dB, will result if a system has 1 mV of noise and 1000 mV of signal voltage?

a) 10 dB
b) 20 dB
c) 60 dB
d) None of the above

14. Which of these could be classified as an internal noise source?

a) Atmospheric noise
b) Cosmic noise
c) Johnson noise
d) None of the above

15. What noise voltage will be generated across a 100K resistor at room temperature (24 degrees Celsius) if the circuit's bandwidth is 1 MHz? (k=1.38 x 10-23 J/K)

a) 40.5 uV
b) 0.5 uV
c) 20 uV
d) None of the above

16. What noise voltage will be generated across a 47K resistor at room temperature (24 degrees Celsius) if the circuit's bandwidth is 500 KHz? (k=1.38 x 10-23 J/K)

a) 40.5 uV
b) 19.6 uV
c) 20 uV
d) None of the above

17. What is the information frequency in the AM signal pictured above?

a) 1 KHz
b) 2 KHz
c) 4 KHz
d) 5 KHz

18. A certain AM transmitter produces 10W of power into a 50 Ohm load with no modulation. What total power will be produced at 100% modulation?

a) 15 W
b) 20 W
c) 30 W
d) None of the above

19. What is the percentage of modulation for the AM signal above?

a) 50%
b) 60%
c) 70.7%
d) None of the above

20. What is the total bandwidth of the AM signal pictured above?

a) 500 Hz
b) 1 KHz
c) 2 KHz
d) 4 KHz

21. Which of these is a consequence of overmodulating an AM transmitter?

a) Distortion of the information
b) Splatter (Excessive bandwidth)
c) Both A and B
d) None of the above

22. What is the total bandwidth of the AM signal pictured above?

a) 2 KHz
b) 700 KHz
c) 10 KHz
d) None of the above

23. An AM signal was measured on an oscilloscope. The readings were Vmax=400 V, and Vmin = 100V. What is the percent modulation?

a) 33.3%
b) 60 %
c) 75 %
d) None of the above

24. An AM signal was measured on an oscilloscope. The readings were Vmax=300 V, and Vmin = 150V. What is the percent modulation?

a) 33.3 %
b) 50 %
c) 75 %
d) None of the above

25. What is the frequency of the upper sideband for an AM transmitter with a carrier frequency of 710 KHz and an information frequency of 5 KHz?

a) 710 KHz
b) 711 KHz
c) 712 KHz
d) None of the above

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