Artificial Satellite Types

Written by Gary Davis


Artificial Satellite Types

By Gary Davis

Dish-Network-Satellite-TV.ws

Webmasters: You may reprint this article in its entirety, providing you leaverepparttar Byline and Aboutrepparttar 109908 Author sections intact, includingrepparttar 109909 links to Dish Network Satellite TV.

A celestial body orbiting another celestial body of larger size is a satellite. An artificial satellite is a manufactured object or vehicle intended to orbitrepparttar 109910 earth,repparttar 109911 moon, or another celestial body. Since October 4th, 1957 humanity is capable of putting artificial satellites in orbit aroundrepparttar 109912 earth. The Russians wererepparttar 109913 first with Sputnik; a small satellite that orbitedrepparttar 109914 earth for a couple of months and transmitted beeps for 21 days.

The USA launched its first satellite on January 31st, 1958. This satellite was named Explorer 1, and throughrepparttar 109915 data transmitted back to earth by Explorer 1, scientists discoveredrepparttar 109916 van Allen radiation belts, zones in space aroundrepparttar 109917 earth, andrepparttar 109918 planets Jupiter and Saturn, containing high-energy protons and electrons.

50 years ago artificial satellites did not exist. Since Sputnik more than 4800 satellites have been launched by governments and private companies aroundrepparttar 109919 world. Satellites are used for satellite TV of course, but there are many more purposes for satellites.

Types of Satellites

The Moon is a satellite ofrepparttar 109920 earth;repparttar 109921 earth is a satellite ofrepparttar 109922 sun. The first is called a moon,repparttar 109923 second a planet. Man made (artificial) satellites orbit any celestial body and are always called a satellite, whether they orbitrepparttar 109924 earth,repparttar 109925 moon,repparttar 109926 sun or any other celestial body.

We use satellites for different purposes and all satellites can be placed in one ofrepparttar 109927 following categories:

Communications Satellites

Distribution of television and audio signals, and telephone connections via satellite are done by Communications Satellites. These types of communications typically need a satellite in geostationary orbit. In 1964repparttar 109928 US Department of Defense launchedrepparttar 109929 first satellite that was placed in geostationary orbit. This satellite was named Syncom 3.

Today geostationary satellites are used to provide voice, audio and video communications like satellite TV by Dish Network Satellite.



What is HDTV?

Written by Gary Davis


What is HDTV?

By Gary Davis Dish-Network-Satellite-TV.ws

Webmasters: You may reprint this article in its entirety, providing you leaverepparttar Byline and Aboutrepparttar 109907 Author sections intact, includingrepparttar 109908 links to Dish Network Satellite TV. High Definition TeleVision is what HDTV literally means. But high definition compared to what? In order to answer this question, we need to know a bit aboutrepparttar 109909 original analog TV system.

Analog TV

30 images per second (in Europe 25) are shown by normal analog TV sets. It does this by writing image lines horizontally, 525 lines in one image (In Europe 625) onrepparttar 109910 screen. The number of pixels on one line is about 500. This would be a definition of 500 pixels per line by 525 (or 625) lines. Compared to modern computer monitors this is really bad. Evenrepparttar 109911 lowest resolutions monitors have higher resolutions (640 x 480) than an analog TV.

HDTV - High Definition TeleVision

HDTV is high resolution Digital TeleVision (DTV) combined with Dolby Digital Surround Sound (AC-3). There are 18 different formats defined for Digital TV of which 6 are considered to be HDTV:

Active Lines Per Picture Pixels Per Line Aspect Ratio Frame RateScanning Approach

The difference between Progressive and Interlaced is not difficult. It has to do with how one image is built up. With interlaced technologyrepparttar 109912 odd lines are shown first and thenrepparttar 109913 even lines are shown. The lines are shown in this order: 1,3,5,….521, 523, 525, 2, 4, 6,…. 522, 524, 1, 3, etc. This means that every 1/60 of a second a half image is shown. This often results in flickering, which can be tiring forrepparttar 109914 eyes.

Progressive technology manages to show a whole image every 1/60 of a second, resulting in a much smoother picture.

How Is HDTV Better?

  • Normal TV has a resolution of about 210.000 pixels. An HDTV screen has a resolution of upto 2.000.000 pixels, which gives up to 10 times more picture detail.


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