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-

 News trom China

Outcry as Chinese school makes iPads compulsory

Apple produets are incredibly popular in China, but not everyone can afford them A school in northern China has been criticised for enforcing iPad learning as part of its new curriculum, it's reported.

According to China Economic Daily, the Danfeng High School in Shaanxi province recently issued a notice saying that, “as part of a teaching requirement, students are required to bring their own iPad” when they start the new school year in September. Stafftold the paper that using an iPad would “improve classroom efficiency”, and that the school would manage an internet firewall, so that parents would not have to worry about students using the device for other means.

However, China Economic Daily says that after criticism from parents, who felt that it would be an “unnecessary financial burden”, headmaster Yao Hushan said that having an iPad was no longer a mandatory requirement. Mr Yao added that children who don't have a device could still enrol, but that he recommended students bring an iPad as part of a “process of promoting the digital classroom”.

The incident led to lively discussion on the Sina Weibo social media platform. “Those parents that can't afford one will have to sell a kidney!” one user quipped.

Others expressed concerns about the health implications of long-term electronic device use. “I worry about their Vision,” one user said, and another said they would all become “short-sighted and have to wear glasses.”

But others felt that it was a good move in line with new modem ways of teaching. “They are affordable for the average family,” one said, “they don't necessarily need to buy the latest model.”

Reporting by KerryAllen

Taken from: www.bbc.com/news/blogs-news-from-elsewhere