1. What is an analog-digital converter?

An Analog-Digital Converter (ADC) is a widely used electronic component that converts an analog electric signal (usually a voltage) into a digital representation. The ADCs are at the front-end of any digital circuit that needs to process signals coming from the exterior world. Its schematic symbol is:

The output of a microphone, the voltage at a photodiode or the signal of an accelerometer are examples of analog values that need to be converted so that a microprocessor can work with them.

2. How does the ADC convert a signal?

Many ways have been developed to convert an analog signal, each with its strengths and weaknesses. The choice of the ADC for a given application is usually defined by the requirements you have: if you need speed, use a fast ADC; if you need precision, use an accurate ADC; if you are constrained in space, use a compact ADC.

All ADCs work under the same principle: they need to convert a signal to a certain number of bits N. The sequence of bits represents the number and each bit has the double of the weight of the next, starting from the Most Significant Bit (MSB) up to the Least Significant Bit (LSB). In a nutshell, we want to find the sequence of bits bN−1, bN−2, ..., b0 that represents the analog value Vin as Vin=∑n=0N−1bn2nVref2N.

                                (www.onmyphd.com/?p=analog.digital.converter. Adaptado)

Instruction: Answer questions 36 to 40 based on the following text.

Klingon to Dothraki: Invented languages gain popularity

1. The idea of invented languages is not new. People have been trying to create new tongues
2. for a long time. One of the most famous examples is Esperanto, created by Ludwik Zamenhof
3. in 1887 which he hoped would become __ globally spoken unifying language. The fact that it
4. is based on 16 very simple rules and took words from languages already present makes it very
5. easy to learn. This was a conscious decision by Zamenhof who hoped that if everyone spoke
6. one language, there would be fewer wars and conflicts.
7. So far, none of the existing constructed languages has achieved a large number of
8. speakers. Klingon, the invented language of Star Trek has around 20-30 speakers. Na’vi, the
9. language created for the movie “Avatar” has one fluent speaker, 10 intermediate speakers,
10. and over forty novices. Dothraki, which was crafted specifically for __ series Game of Thrones,
11. boasts seven intermediate speakers and around a hundred novices. For now, Garadálava has
12. exactly one speaker: Fynn Schlemminger himself.
13. However Esperanto is a notable exception: it’s estimated that the language has around
14. some 1,000 native speakers, and many parents teach it to their children. TV series, movies,
15. books, and especially the Internet have given invented languages a chance like never before.
16. According to the BBC, Esperanto, which was created almost exactly 100 years ago, is currently
17. experiencing a boost, mostly thanks to the language learning app Duolingo, and a highly
18. engaged online community. Wikipedia is also available in this language.
19. With the amount of time and effort it takes to learn a new language, it is rather unlikely
20. that __ invented tongue will achieve world domination in the same way English has. But it is
21. clear that there is rising interest in creating new languages. “Yes, there might be more of them
22. in the future, or more people will try their hand at it,” said Carpenter.

Fonte: adaptado de http://www.euronews.com/2018/04/25/from-klingon-to-dothraki-is-inventing-your-own-language-that-hard-