1. In AM, the carrier is changed by a modulating signal. What parameter of the carrier is changed?
2. For a four-quadrant linear multiplier, what is the output voltage, given input voltages of Vx = +2 V and Vy = –10 V?
3. The output spectrum of a ________ modulator includes upper-side and lower-side frequencies and the carrier frequency.
4. Amplitude modulation is a ________ process.
5. What does VCO stand for?
6. A phase-locked loop (PLL) is a feedback circuit consisting of a
7. If a 1 MHz carrier is amplitude modulated with a 5 kHz audio signal, the upper-side frequency is ________ kHz.
8. The purpose of the balanced modulator is to remove the carrier frequency.
9. The mixer takes the RF signal along with the audio signal to produce the IF signal.
10. The IF of an FM receiver operates at a center frequency of 455 kHz.
11. A balanced modulator is used in standard AM to obtain the sum and difference frequencies.
12. The demodulator recovers the audio signal from the IF output.
13. Selectivity in a receiver is provided by the resonant circuits of the IF section.
14. An AM signal is made up of a carrier, an upper-side frequency, and a lower-side frequency.
15. Frequency modulation is achieved by varying the frequency of an oscillator with a modulating signal.
16. A VCO is a variable capacitance oscillator.
17. Amplitude modulation is the process of varying the radio frequency with the modulating frequency.
18. A certain fiber-optic cable has the following characteristics: n1 = 1.82 and n2 = 1.73. What is the value of θc?
19. An AM demodulator can be implemented with a linear multiplier followed by a ________ filter.
20. The intermediate frequency in a standard AM receiver is
21. In order for a light ray to propagate along a fiber-optic cable, what must the relationship be between the angle of incidence and the critical angle?
22. Light may be propagated along a fiber-optic cable in which of the following modes?