CET quiz, part IX -- Radio & TV (ET/D, Nov. 1981)

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This entire quiz is on radio and television fundamentals. It should be a good review to help you get ready for the CET tests. Why not take the test soon and surprise yourself with how much electronics knowledge you really have and didn't realize? See if you can get more than 75% on this quiz.

By Frank Egner


Figure 1 used for questions 1 through 15.

Questions 1 through 15 refer to figure 1

1. The block diagram indicates this is a:

a. AM stereo receiver.

b. FM stereo receiver.

c. Shortwave receiver.

d. May be any of these.

2. Block 1 will accept frequencies of:

a. 540 to 1610 KHz.

b. 30 to 50 MHz.

c. 88 to 108 MHz.

d. 1540 to 2610 KHz.

3. If an SCA signal is being received, it could be recovered at the output of block:

a. 6

b. 4

c. 2

d. 5

4. A complementary-symmetry amplifier circuit might be used in:

a. Blocks 7 and 8.

b. Block 6.

c. Block 4

d. Blocks 2 and 3.

5. The signals present at the output of block 5 during a stereo broadcast are:

a. The monaural and pilot signals.

b. L + R and L - R sidebands.

6.

7.

8.

9.

0 rier of

a. 19 KHz.

b. 10.7MHz.

c. 455 KHz.

d. 38 KHz.

If present, the SCA signal must be filtered out. The SCA filter must respond to:

a. 4.5 MHz.

b. 10.7 MHz.

c. 67 KHz.

d. 38 KHz.

. Good quality receivers include block

1. An advantage of block 1 is:

a. Broadcast band image rejection.

b. Improved signal to noise ratio.

c. Broader selectivity.

d. More than one but not all above.

11. There is no receiver output. The first test should be made at:

a. Block 9.

c. L - R sidebands and monaural signals.

d. L + R, pilot, and L - R sidebands.

The range of frequencies that may appear at blocks 7 and 8 area:

a. 50 Hz to 15 KHz.

b. 60 Hz to 5 KHz.

c. 50 Hz to 20 KHz.

d. 60 Hz to 7.5 KHz.

Some receivers stabilize the local oscillator by using

a. AGC.

b. AFC.

c. ACC.

d. AFT. To decode the stereo signal, a car must be developed.

b. Blocks 7 and 8.

c. Block 5.

d. Block 3.

12. The bandwidth authorized by FCC for this type transmission is:

a. 75 KHz.

b. 150 KHz.

c. 200 KHz.

d. 20 KHz.

13. The circuit within block 5 could be a:

a. Grid or base leak detector.

b. Slope detector.

c. Ratio detector.

d. Infinite impedance detector.

14. The block least likely to use a unipolar device is:

a. Block 1.

b. Block 2.

c. Block 4.

d. Blocks 7 and 8.

15. Block 3 must be operational over the range of:

a. 98.7 to 118.7 MHz.

b. 995 to 2065 KHz.

c. 88.7 to 108.7 MHz.

d. 40.7 to 60.7 MHz.

16. Which of the following are compatible by FCC regulation?

a. Monaural and multiplex FM receivers.

b. Monochrome and color TV receivers.

c. Both a and b.

d. Neither a nor b.

17. In the 6 MHz TV channel at the transmitter, the sound carrier is located exactly:

a. 250 MHz below the channel up per frequency.

b. 250 KHz above the channel lower frequency.

c. 4.5 MHz below the picture carrier frequency.

d. 920 KHz below the color subcarrier.

18. In the TV IF passband, the color subcarrier is located:

a. 3.58 MHz above the picture carrier.

b. 920 KHz above the sound carrier

c. 1.5 MHz below the picture carrier.

d. 600 KHz below the sound carrier.

19. To develop linear sweeps in vacuum tube TV receivers, the yoke must be driven by:

a. Sawtooth voltages.

b. Trapezoidal currents.

c. Sawtooth currents.

d. Trapezoidal voltages.

20. Coaxial cables may be connected to TV receivers using a balun. This device is:

a. An impedance matching device.

b. An attenuator network.

c. An RC time constant network.

d. A circuit to attenuate ghosts.

21. The vertical sync pulse is used to initiate:

a. The vertical blanking period.

b. The start of the vertical trace.

c. The horizontal blanking period.

d. The vertical retrace cycle.

22. The vertical sync pulse is serrated into six pulses. This is necessary to:

a. Properly charge the integrator.

b. Prevent overcharging the differentiator.

c. Maintain horizontal stability.

d. Prevent vertical retrace lines.

23. Maximum conduction of the video diode detector:

a. Can be during sync or video time.

b. Occurs during video signal time.

c. Always occurs during sync pulse time.

d. Occurs during brightest picture peaks.

24. A TV receiver is tuned to channel 10 (192-198 MHz). The LJO operates at 239.25 MHz. The sound and video IFs at the mixer output are:

a. S: 41.25 MHz, V: 45.75 MHz.

b. S: 47.25 MHz, V: 51.75 MHz.

c. S: 41.5 MHz, V: 46.0 MHz.

d. S: 31.5 MHz, V: 36.0 MHz.

25. Video amplifiers use peaking coils to compensate for attenuation of:

a. Audio frequencies.

b. Mid-range frequencies.

c. Low frequencies.

d. High frequencies.

Answers to Electronic Quiz:

1.b 6.a 11.a 16.c 21.d
2.c 7.b 12.b 17.a 22.c
3.d 8.d 13.c 18.b 23.c
4.a 9.c 14.d 19.d 24.c
5.d 10.b 15.a 20.a 25.d

(source: Electronic Technician/Dealer)

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