Lesson 14. The TV set
I. Просмотрите текст и определите, верны ли следующие предложения.
1.The TV set allows us to watch programs and to play games.
2. The inside of the screen is coated with crystals of different colors.
3. Each electronic beam must hit only the appropriate colored phosphor.
4. Magnetic fields do not have any function.
The TV set is the central element of any audio/visual setup. It allows us to watch programs received by antenna, cable or satellite, and movies via out VCR. We can also use the TV as a monitor to play games on game computers and CD-i players.
The central component of a TV set is the cathode ray tube (CRT). The components of a cathode ray tube are the cone, the screen, the electron gun, the deflection coil and the shadow mask.
The cone and the screen are welded together to from glass envelope into which the shadow mask and the electron gun are positioned. The deflection coil is placed around the outside of the neck of the cone.
The inside of the screen is coated with light sensitive red, green and blue crystals called phosphors. These phosphors are arranged in groups of three (or triads) of one blue, one red and one green. Three electron beams are generated by the electron gun; one for each color, which directed by the beams.
In order to produce a correctly colored image each electron beam must hit only the appropriate colored phosphor. To ensure such accuracy, a shadow mask is used as a filter. The shadow mask is a metal plate which is the same shape as the screen and has the same number of holes as the number of triads on the screen. Each hole has a corresponding triad of phosphors which prevents adjacent triads from being influenced.
The beams of the electron gun must be an alignment of the beams onto the mask. This is performed by an electromagnet within the gun.
The electromagnetic deflection coil surrounds the neck of the picture, ensuring accurate deflection of the beam. Electrical signal transmitter enough the deflection coil generate precisely focused magnetic fields. These magnetic fields control the position of the electron beam vertically are horizontally.
II. Следующие слова и выражения встречаются в тексте. Переведите их на русский язык при помощи словаря.
Setup, to allow, cone, a screen, cathode ray tube, an electron gun, deflection coil, a shadow mask, a neck, to position, to arrange, to hit appropriate, accuracy, to prevent, adjacent, to converge.
III. Составьте собственный словарь терминов.
IV. Выберите попарно слова с противоположными значениями.
A) outside, to arrange, correct, left, up, to prevent, to converge.
B) Wrong, to promote, to disperse, down, inside, to scatter, right.
V. Вставьте предлоги, где необходимо
1. It prevents triads … being influenced.
2. We can play … games.
3. There must be an alignment of the beams … the mask.
4. Many programs may be received … a satellite.
5. The phosphors are illuminated … the beams.
VI. Пользуясь текстом, составьте вопросы так, чтобы получили следующие ответы
1. We can use a TV set as a monitor.
2. The cone and the screen must form an envelope.
3. The shadow mask is a metal plate.
4. The screen is one of the components of a TV set.
5. It is done in order to produce a correctly colored image.
VII. Пользуясь знаниями об инфинитиве определите, каким членом предложения является инфинитив и правильно переведите предложения на русский язык.
1. Each electron beam must hit only the appropriate colored phosphor.
2. The cone and the screen are welded together to from an envelope.
3. Nature has many secrets to be discovered yet.
4. He made me believe his words.
5. The TV set allows us to watch programs.
6. I’m sorry to have bothered you.
7. To ensure such accuracy, a shadow mask is used as a filter.
VIII. Прочитайте и переедите текст
Home work: Перескажите текст
Lesson 15. COLOR AND SOUND IN TV
Просмотрите текст без словаря и передайте основную идею каждой его части на русском языке.
COLOR
In a black – and – white TV set, only one pixel type covers the entire screen. A black – and – white tube therefore only needs a single cathode gun. Variation in the brightness of the beam determines how much a pixel will light up, resulting in shades of black – white.
A color tube has three beams: one for the red, one for the blue, and one for the green pixels (phosphors). The three electron beams scan the screen as if they were one. The screen is covered with three types of phosphor dots and each type lights up in one of the primary colors of red, green or blue when it is struck by an electron beam. (The primary colors of red, green and blue [RGB] form the basis of all other colors.) A complete picture on a 28” TV contains approximately 450,000 pixels.
The ratio of the illuminated phosphors determines the total color. If, for instance, the beam that strikes the blue phosphor is suppressed, allowing only the red and green phosphors to glow, to the human eye the red and green will blend together to form bright yellow. By varying the brightness of one or more electron beams, the color pattern changes accordingly, which means that every possible color in varying brightness can be generated. When the camera scans a bright image, the transmitted signal has a higher. Voltage than when scanning a dark image. The electron beam in the tube immediately responds and the same relative brightness also appears on the screen, pixel by pixel.
Sound
Sound is becoming increasingly important in television. The sound supports the image and adds another dimension to make the viewer feel more mvolved.TV sets come in mono, stereo and hi-fi. Properly installed loudspeakers send the sound forward. Higher quality sets have low frequency speakers that send their signals sideways and also have much smaller high-frequency speakers placed somewhere in the lower parts or to the sides of the set. As low frequencies travel in all directions, low-frequency speakers do not need to point at the viewer.
Speakers
While a TV set can be connected to hi-fi speakers, the main disadvantage is that the speakers are distant from the TV set. This often results in the sound coming from a different direction from the picture. This feels unnatural and is not a long-term solution. Therefore, stereo TV sets require matching loudspeakers, either built in to the right and the left, or placed right next to them as separate speakers. The best solution is special TV loudspeakers that are shielded to prevent magnetic emissions. When emissions from the speakers start to interfere with the electron beams, they can cause serious image distortions, especially color distortions.
Surround Sound
Surround Sound offers an additional dimension to sound. Many movies released on videocassette, Video CD or Laserdisc have stereo surround sound. Surround sound conveys not only the standard left and right stereo, but also the center channel information for dialogue and surround channel information for surround effects. The center channel information is transmitted as a mono channel which mixes the left and right signals. The surround sound goes in as a difference signal (left minus right) with noise reduction. Requirements for surround sound reproduction are a surround sound speaker setup and TV-audio/video equipment that can decode surround sound, and software recorded in surround sound. If the equipment Is not able to decode surround information, it will reproduce the sound in normal stereo.
Dolby Stereo can be decoded in two ways for Dolby Surround Sound.
The simplest form is called Dolby Surround. The surround channel is extracted and run through a Dolby noise reduction chip (with a little time delay of 15 to 30 milliseconds). The signal is sent to the speakers in the back of the room, which makes it sound more advanced than Dolby Surround. It uses the center channel information to project dialogue from the front center speaker. Also the surround channel signal gives a more realistic sound. Whereas the center signal used in Dolby Surround is also reproduced in the front speakers, with Pro Logic this not the case.
II.Соедините английские слова с их русскими эквивалентами. Запомните данные слова.
Pixel громкоговоритель, репродуктор
To cover искажение
to determine восхищение
to suppress защипывать, экранировать
Involved покрывать
Loudspeaker пиксель
solution определять, устанавливать
emission сложный, запутанный
distortion сдерживать, подавлять
to convey решение, объяснение
excitement излучение, распространение света
to shield передавать звук
III. Ответьте на вопросы.
1. Why does a black – and white tube need only signal cathode gun?
2. How many beams has color tube?
3. What determine the total color?
4. What does the sound do?
5. What is the best solution for speakers?
6. What does surround sound convey?