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1. What is the function of an RF bypass capacitor?

a) To couple signal from one stage to the next
b) To couple RF energy into the antenna
c) To force RF energy to go to ground
d) None of the above

2. A certain high-level transmitter produces 10 Watts of carrier power. How much power must the audio amplifier produce to 100% modulate this transmitter?

a) 2 Watts
b) 4 Watts
c) 8 Watts
d) 5 Watts
e) None of the above

3. What class of amplifier would be serve as a modulator?

a) Class A
b) Class B
c) Class C
d) None of the above

4. Which of these is an important property for a modulator stage to have?

a) High voltage gain
b) High power gain
c) Low input-impedance
d) Non-linear transfer characteristic

5. Where would one expect to find an RF bypass capacitor connected within a radio transmitter?

a) Between the final PA stage and the antenna
b) Between the oscillator and buffer amplifier
c) Between a power supply line and ground
d) None of the above

6. Where does the modulation take place at in a high-level transmitter?

a) At the oscillator
b) At the final power amplifier
c) At the buffer amplifier
d) Before the final power amplifier

7. What is the purpose of a buffer amplifier?

a) To provide a large voltage gain
b) To isolate the oscillator from the next stage
c) To reduce distortion of the carrier sine wave
d) None of the above

8. The oscillator in a certain transmitter produces 1 mW of output. The signal is subsequently amplified in the following stages:

Buffer: +10 dB
Modulator: +6 dB
Driver: +10 dB
Final: +13 dB

What is the final output power of this transmitter in Watts?

a) 8 Watts
b) 4 Watts
c) 400 mW
d) None of these

9. What type of oscillator is pictured above?

a) Colpitts
b) Hartley
c) Armstrong
d) Pierce
e) None of the above

10. What is the operating frequency of the oscillator pictured above?

a) 599.412 KHz
b) 847.697 KHz
c) 455.000 KHz
d) None of the above

11. In order for an oscillator to start, the loop gain must be:

a) Greater than 1
b) Greater than or equal to 1
c) Less than 1
d) None of the above

12. What type of oscillator is pictured above?

a) Colpitts
b) Hartley
c) Armstrong
d) Pierce
e) None of the above

13. A certain crystal has the following characteristics: Ls=1 H, Cs=.001 pF, Rs = 150 Ohms, Cm = 5 pF. At parallel-resonance, what is the approximate terminal impedance of the unit?

a) 30 + j125 Ohms
b) 30 - j150 Ohms
c) 150 Ohms (Equal to Rs)
d) Infinity (Open Circuit)

14. Another name for the parallel-resonant frequency of a crystal is the:

a) Pole
b) Zero
c) Maximum
d) Minimum

15. Another name for the series-resonant frequency of a crystal is the:

a) Pole
b) Zero
c) Maximum
d) Minimum

16. A certain crystal has the following characteristics: Ls=1 H, Cs=.001 pF, Rs = 150 Ohms, Cm = 5 pF. What is the parallel-resonant frequency of the unit?

a) 5.032921 MHz
b) 4.986123 MHz
c) 5.033424 MHz
d) None of the above

17. What is meant by the term "high-side injection?"

a) The local oscillator operates with a large AC output signal
b) The IF amplifier uses negative-bias to produce AGC
c) The local oscillator operates above the frequency of the RF carrier
d) None of the above

18. What is the advantage of having a constant-frequency amplifier (the IF amplifier) in a superheterodyne receiver?

a) The gain can be held constant
b) The noise is minimized
c) The bandwidth will be constant
d) None of these

19. The two signal components that are produced in a diode-type AM detector circuit are:

a) The upper and lower sidebands
b) A DC level and the AC information signal
c) The carrier frequency and sidebands
d) None of these

20. Why can't TRF receivers be constructed for high-frequency (above 1-2 MHz) use?

a) Insufficent "Q" is available from discrete LC components at these frequencies
b) Transistors and ICs have insufficient gain at these frequencies
c) Detector circuits produce excessive distortion at these frequencies
d) None of the above

21. In a superhet receiver, the difference between the preselector and local oscillator frequencies should always be:

a) The IF frequency
b) The carrier frequency
c) One-half the local oscillator frequency
d) None of these

22. What section of a superheterodyne receiver is responsible for attenuation of the image frequency?

a) Detector
b) Preselector
c) Local Oscillator
d) None of these

23. What is the name of the amplifier that operates at a constant frequency in a superhet receiver?

a) The audio amplifier
b) The RF amplifier
c) The IF amplifier
d) None of these

24. A mixer has two frequencies being applied, 700 KHz and 1000 KHz. Which of these gives the ideal output frequencies?

a) 700 KHz, 1000 KHz
b) 700 KHz, 1000 KHz, 1700 KHz
c) 700 KHz, 1000 KHz, 1700 KHz, 300 KHz
d) None of these

25. What section of a superheterodyne receiver determines the receiver's bandwidth and selectivity?

a) Preselector
b) IF Amplifier
c) Detector
d) Audio Amplifier
e) None of the above

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