Задание. Изучите классификацию сигналов по форме и по информативности, па-раметры аналоговых и цифровых сигналов.
Задача Канал тональной частоты занимает полосу частот от 300 до 3400 Гц. По каналу в течение 30 с передается телефонное сообщение и такого же содержания теле-графное сообщение равномерным кодом с длительностью каждой посылки 20 мс. Дина-мические диапазоны сигналов принять равными. На одном и том же графике показать объем обоих сигналов, выделив их разным цветом.
Вопросы для самоконтроля:
1. Назовите основные параметры аналоговых и цифровых сигналов
2. Охарактеризуйте периодические сигналы и их спектры
3. Охарактеризуйте непериодические сигналы и их спектры.
4. Приведите классификацию сигналов электросвязи
САМОСТОЯТЕЛЬНАЯ РАБОТА №3
Тема 2.1
Преобразование гармонического и бигармонического сигналов в нелинейной цепи
Задание. Внимательно прочтите слова, постарайтесь понять, о чем идет речь. Каж-дое слово должно быть использовано один раз и в том падеже и числе, которое указано в задании. Возможно несколько вариантов, главное, чтобы смысл фразы оставался правиль-ным. Составьте фразы:
1 Нелинейной, аппроксимация, виде, приближенное, в, представление, уравнения, характеристики, это.
2. Представление, аппроксимации, реальной, уравнением, характеристики, уравне-нием, его, неалгебраическим, элемента, характеристики, это, нелинейного, трансцендент-ным.
Запишите фразу, заполнив пробелы, отмеченные многоточием:
Кусочно-линейная аппроксимация – это … реальной плавно меняющейся зависимости отрезками прямых, являющихся …в нескольких ее точках.
Составленные фразы запишите в конспект.
Вопросы для самоконтроля:
1. Чем отличается спектр отклика при воздействии на нелинейный элемент гармоническим сигналом от спектр отклика при воздействии на него бигармоническим сигналом?
2 Методы спектрального анализа выходного сигнала нелинейной цепи.
3 Параметры и характеристики нелинейных элементов
4 Какие виды аппроксимации ВАХ Вы знаете?
САМОСТОЯТЕЛЬНАЯ РАБОТА №4
Тема 2.2
Умножение частоты. Преобразование частоты
Задание. Внимательно прочтите слова, постарайтесь понять, о чем идет речь. Каждое слово должно быть использовано один раз и в том падеже и числе, которое указа-но в задании. Возможно несколько вариантов, главное, чтобы смысл фразы оставался пра-вильным. Составьте фразы:
1. Кратным, одного, умножение, увеличением, процесса, это, частоты, в, процесс, колебания, колебаний, сопровождающийся, преобразования, колебательного, другой, ча-стоты.
Запишите фразу, заполнив пробелы, отмеченные многоточием:
При умножении частоты методом отсечки выходного тока чем … угол отсечки, тем …коэффициент умножения.
Изучите: принцип умножения частоты, схемы умножителя частоты, принцип пре-образователя частоты, схема преобразователя частоты, области применения.
Вопросы для самоконтроля:
1 В чем заключается принцип умножения?
2 Что называется углом отсечки?
3 В чем заключается принцип преобразователя частоты?
4 Поясните схемы преобразователя частоты
САМОСТОЯТЕЛЬНАЯ РАБОТА №5
Тема 2.3
Автоколебательные системы
Задание. внимательно прочтите слова, постарайтесь понять, о чем идет речь. Каж-дое слово должно быть использовано один раз и в том падеже и числе, которое указано в задании. Возможно несколько вариантов, главное, чтобы смысл фразы оставался правиль-ным. составленные фразы запишите в конспект. Составьте фразы:
1. Увеличением, увеличение, обратной, колебаний, мягком, амплитуды, при, со-провождается, режиме, плавным, самовозбуждения, связи.
2. Усилительного, связи, автогенератор, и, из, обратной, элемента, состоит, нагруз-ки.
Вопросы для самоконтроля:
1. Что называется автогенератором?
2. Приведите классификацию автогенераторов
3. От чего зависит частота колебания LC – генератора?
4. Поясните работу автогенераторов в стационарном режиме
Английский
Язык
Australia
Australia is the only country in the world that is also a continent. It is the sixth large country and the smallest continent. Australia lies between the South Pacific Ocean and the Indian Ocean. It is situated about 11 000 km southwest of North America and about 8200 km southeast of mainland Asia. The name of the country comes from Latin word «australis»which mean southern. The country's official name is Commonwealth of Australia.
The Commonwealth of Australia is a federation of states. Australia has six states — New South Wales, Queensland, South Australia, Tasmania, Victoria and Western Australia. Each state has its government. Australia has two territories — the Australian Capital Territory and the Northern Territory. The capital of the country is Canberra.
Australia is a constitutional monarchy like Great Britain. The nation is administered under written constitution. The British monarch, Queen Elizabeth II, is also queen of Australia and country's head of state. But the queen has little power in the Australian government. She serves mainly as a symbol of long historical tie between Great Britain and Australia. Australia is a member of the Commonwealth of Nations which is an association formed by Britain and some of its former colonies.
Australia is one of the world's developed countries. Australia has modern factories, highly productive mines and farms, and busy cities. It is the world's leading producer of wool and bauxite the ore from which aluminium is made). It also produces and exports large amounts of other minerals and farm goods. Income from the export enables Australians to have high standard of living. The most important trading partners of Australia are Japan and the United States.
The Great Barrier Reef on the coast of Queensland is a garden under the sea. There are 1,400 different kinds of fish, and more than 300 kinds of coral. Tropical fruit and flowers grow on the beautiful islands. It's not surprising that more holiday-makers come to Queensland every year.
Tasmania, the island south of Australia is small. It is the same size as England. It is also very different from the other states. There are no deserts in Tasmania. It often rains, both in winter and summer. Only a half of million people live in Tasmania, and a large part of the island is still covered with wild, beautiful wild forests. These forests are full of wonderful flowers and interesting animals.
In the Northern Territory you will find the red heart of Australia. And it really is red, with red rocks, red sand, and red skies in the evening. Every year, thousands of tourists visit Ayers Rock and a strange group of huge red stones called «the Olgas». But these «places are also to the holy Aboriginals. They believe that the land itself has life.
Sydney is the best known place in New South Wales. In fact, it's the best known place in Australia. But New South Wales has more than cities. There are, for example, the Blue Mountains. They are covered with forests of blue colored eucalyptus trees. The air above the forest contains millions of microscopic drops of
eucalyptus oil. When the sun shines, the air of the Blue Mountains is a real beautiful blue.
Less then a hundred years ago, there was nothing except sheep in Canberra. But then Australians decided to build a capital city. The Work began in 1913. Now, Canberra is an international city, full of diplomats and government offices. It's a beautiful place, with parks, lakes, big open streets and fine buildings.
Australia is sometimes called «the lucky country». One reason is the wonderful riches under the earth: gold, silver, iron, coal and many precious metals. The Bass Strait of the coast of Victoria has been one of the country's biggest oil fields for many years.
South Australia is the driest of all the states, but it does have Murray River. The river brings greenness and life to the south-east corner. In the early history of Australian, the Murray River was South Australia’s main road. Before real roads and railways came, the river carried people and goods from the east up into the country. Some towns on the Murray still keep the old river boats, and visitors can ride on them.
There are two kinds of gold in Western Australia. First, there's real kind - the kind that comes out of the ground. Gold was found in Kalgoorlie in 1893, and the «Golden Mile» was for a time the most expensive piece of land in the world. Kalgoorlie still exports some gold, but the new gold of Western Australia is wheat. Big farms grow millions of tons of wheat every year, and wheat has become Australia’s second biggest export.
Vocabulary
to lie – находиться;
to be situated – бытьрасположенным;
mainland – материк;
Latin – латинский;
Commonwealth of Australia – АвстралийскийСоюз;
federation – федерация;
state – штат;
territory – территория;
capital – столица;
government – правительство;
tie – связь;
CommonwealthofNations – БританскоеСодружествонаций;
income – доход;
standard of living – уровеньжизни;
bauxite – бокситы, алюминиеваяруда;
holiday-maker – турист, отдыхающий;
island – остров;
wild – дикий;
eucalyptus – эвкалипт;
riches – богатства;
industry – промышленность;
oil – нефть.
New Zealand
The British colony of New Zealand became an independent dominion in 1907. It supported the UK militarily in both World Wars.
New Zealand is a group of islands in the South Pacific Ocean, southeast of Australia. The total territory of New Zealand is 268,680 square km. Its climate is temperate with sharp regional contrasts. The landscape of the country is mountainous with some large coastal plains. The highest point is Mount Cook 3,764 meters. Natural resources are: natural gas, iron ore, sand, coal, timber, gold, limestone.
The population of New Zealand is about 3,910,000. About 80% of the population live in cities. English, Maori are both official state languages of the country. Talking about natural hazards, I should notice that earthquakes are common, though usually not severe and there is a volcanic activity in New Zealand. Independence Day is celebrated on September, 26.
Government type is parliamentary democracy. Administrative division is the following: 93 counties, 9 districts, and 3 town districts. Legal system is based on the English law, with special land legislation and land courts for Maoris. Since 6 February 1952 the chief of the state is Queen Elizabeth II, represented by Governor General Dame Silvia Cartwright since 4 April 2001.
Since 10 December 1999, the Head of the government is Prime Minister Helen Clark and Deputy Prime Minister James Anderton. Since 1984 the government has accomplished major economic restructuring, transforming New Zealand from an agrarian economy to a more industrialized, free market economy that can compete globally. New Zealand is heavily dependent on trade — particularly in agricultural products. The main industries are mining, food processing, wood and paper products, textiles, machinery, transportation equipment.
New Zealand's currency is New Zealand dollar. New Zealand is the name of the country that has volcanoes, mountains, tropical forests and rivers of ice. New Zealand is an insular country. It is made up of two big islands: the North and South Islands and many small islands around.
The aborigines of New Zealand are the Maoris. They call New Zealand the Land of the Long White Cloud. The Maoris are one of the Polynesian nations, who made their great journey to New Zealand from Indonesia and the South Pacific in the middle of the 14th century. They sailed in double canoes, open to all weathers. They knew the winds, the ocean flows and the star navigation that is why they reached this land, later called New Zealand and we can call them the Vikings of the Sunrise. Most population of New Zealand lives on the North Island. Here you can also find big volcanoes like Egmont, geysers and lakes of bubbling mud.
The biggest cities of New Zealand are Auckland, Christchurch and Wellington. Wellington is the present capital of New Zealand since 1865, and one of its busiest ports, located at the southern end of North Island, lying among hills an the western side of a natural harbour. It is the third largest city of New Zealand.
Auckland or former capital of New Zealand is the largest city of the state. Christchurch is the second largest city.
South Island is larger than North Island. There are the highest mountains in this part of the country. There you can find the snow-capped Southern Alps, rising 3 764 meters to the tip of Mount Cook (named after Captain Cook who visited the islands before sailing westwards and discovering the eastern coast of Australia).
South Island is very beautiful with its mountains, called Alps, lakes, glaciers and fiords. Here you can see the Sunderland Falls, where water drops from the height of six hundred meters, making these falls one of the highest waterfalls in the world. The climate is mild at all seasons. There is no much difference of temperature between winter and summer. Notwithstanding New Zealand is close to Australia, New Zealand does not have such terrible heat of Australian summers, because the ocean tempers its climate. North Island is where you can find the Maoris, fine people who had lived on these islands hundreds of years before the white man came. Most of them live near Auckland.
The first colonist or settler appeared on the present territory of Wellington in 1840. They called their settlement Britannia.
By the year 1842, there were 3 700 colonists in the settlement of Britannia and later it was renamed into Wellington.
Vocabulary
1) to support – поддерживать;
2) temperate – умеренный;
3) landscape – ландшафт, пейзаж;
4) coastal plain – прибрежнаяравнина;
5) iron ore – железнаяруда;
6) timber – древесина;
7) limestone – известняк;
8) hazard – стихийное бедствие;
9) earthquake – землетрясение;
10) severe – суровый, сильный;
11) legislation – законодательство;
12) chief of state – глава государства;
13) to accomplish – выполнять;
14) to transform – превращать, преобразовывать;
15) to be dependent on – зависетьот;
16) mining – добыча полезных ископаемых;
17) food processing – пищевая промышленность;
18) currency – валюта;
19) volcano – вулкан;
20) to make up – составлять;
21) aborigine – туземец, абориген, представитель коренного населения;
22) Polynesian – полинезийский;
23) Indonesia – Индонезия;
24) to sail – плавать, совершать плавание;
25) double canoe – двойноеканоэ;
26) to reach – достичь;
27) the Vikings of the Sunrise – викингистраныВосходящегоСолнца;
28) bubbling mud – зд. грязевоеозеро;
29) fiord – фьорд;
30) drop – капля;
31) mild – умеренный (о погоде, климате и т. п.);
32) notwithstanding – тем не менее, однако, все же;
33) settler – поселенец;
34) settlement – поселение.