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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 difference between radio stations allows receivers to separate them?

a) Each has a different amplitude
b) Each has a different phase
c) Each has a different frequency
d) None of the above

3. 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

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. Which of these describes the process of modulation?

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

6. 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

7. 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

8. What type of filter is used to separate radio stations in a receiver?

a) Bandpass
b) Highpass
c) Lowpass
d) None of the above

9. 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

10. What is the frequency of the 3rd harmonic for the signal above?

a) 1 KHz
b) 2 KHz
c) 3 KHz
d) None of these

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. What is the relationship of the 2 KHz frequency component to the 1 KHz component in the figure above?

a) The 2 KHz signal is twice the amplitude of the 1 KHz signal
b) The 2 KHz is a distorted form of the 1 KHz signal
c) The 2 KHz signal is the 2nd harmonic of the 1 KHz signal
d) None of the above

13. 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

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. Which type of noise is caused by the thermal agitation of charge carriers within a conductor?

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

16. Noise can best be defined as:

a) Any undesired signal within a system
b) Pulses appearing at the output of a system
c) Distortion at the output of a system
d) None of the above

17. What bandwidth will be required to transmit a 5 KHz sine-wave tone on an AM carrier wave if the carrier frequency is 710 KHz?

a) 10 KHz
b) 5 KHz
c) 1 KHz
d) None of the above

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

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

19. 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

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. 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

22. New frequencies that are generated during the process of modulation are known as:

a) Harmonics
b) Fundamentals
c) Sidebands
d) None of the above

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

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

24. 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

25. 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

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