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6. Match the first part (1-7) of the sentence with the second part (a-g) :

1. Ceramic resonators are …

2. A resonator is…

3. The older chips were …

4. Quartz crystals are …

5. A simple transistor circuit can …

6. A 'mark' is…

7. The 'space' is…

a) … be used to drive the LED.

b) …. seldom used in such handsets.

c) … a device or system that exhibits resonance or resonant behavior.

d) … dedicated to only one of the many protocols that were invented.

e) … is the default signal, which is the off state in the transmitter case.

f) … is then automatically represented by a low level.

g) … much more suitable here, because they can withstand larger physical shocks.

7. Read the supplementary text, translate and entitle it.

Radio-frequency (RF) remote controls are very common. Garage-door openers, car-alarm fobs and radio-controlled toys have always used radio remotes, and the technology is starting to show up in other applications, too. They're still pretty rare in home-theater devices (with the exception of RF extenders, which we'll discuss on the next page), but you will find RF remotes controlling certain satellite-TV receivers and high-end stereo systems. You'll also find Bluetooth-based remotes that control laptops and smartphones. (See How Bluetooth Works to learn about this radio technology.)

Instead of sending out light signals, an RF remote transmits radio waves that correspond to the binary command for the button you're pushing. A radio receiver on the controlled device receives the signal and decodes it. The problem with RF remotes is the sheer number of radio signals flying through the air at any given time. Cell phones, walkie-talkies, WiFi setups and cordless phones are all transmitting radio signals at varying frequencies. RF remotes address the interference issue by transmitting at specific radio frequencies and by embedding digital address codes in the radio signal. This lets the radio receiver on the intended device know when to respond to the signal and when to ignore it. To learn more about the technology of radio-frequency remotes, check out How Remote Entry Works.

The greatest advantage to radio-frequency remotes is their range: They can transmit up to 100 feet from the receiver (the range for Bluetooth is shorter), and radio signals can go through walls. This benefit is why you'll now find IR/RF remotes for home-theater components. These remotes use RF-to-IR converters to extend the range of an infrared remote.

8. Render the text: ir Remote Control Theory.

UNIT 5

Pre-text exercises:

1. Fill in the blanks with the following confusing word: accept / except, past / passed, affect / effect, dessert / desert, further/ farther, well / good, lie/ lay, two/ to/ too.

1. All of the soldiers ___ my brother are out of step. 2. Please ___ this pot of Mom's chicken soup. 3. You may keep all of his gifts ___ the ring. 4. That there are other universes is now an ___ scientific fact. 5. Weather conditions ____ many people's moods. 6. Crossing wire A to wire B will produce an explosive ___. 7. The politician wanted to ___ a change in the system. 8. Karen said that her chocolate ___ was delicious. 9. The world's largest hot desert is the Sahara ___. 10. I wish the professor had discussed this __. 11. Perhaps the poem would be better if the poet had provided ___ detail. 12. A little bit of water in the mixture makes the paint go ___ . 13. Most students write ___ by the time they finish high school. 14. That was a ___ report that you gave yesterday. 15. Unfortunately, I didn't hear your instructions very ___. 16. After I get home from work, I often ___ down for a nap before dinner. 17. Please ____ the papers on Mr. Hart's desk. 18. Write this essay in the ___ tense. 19. By the time I saw him, he had already ___ me. 20. Are you only taking ___ classes? 21. Please don't ask me ___ come. 22. Now, now, don't study ___ often.