Concepts of High Definition Television (HDTV)
October 8, 2008
What is High Definition Television?
A high definition television is a digital television broadcasting system that come with higher resolution compared to the traditional television systems. High Definition Television broadcasts signals digitally, and hence require less bandwidth if the video compression used is sufficient. The term high definition was once used for a series of television systems that were introduced in the year 1930s and 1940s. A HDTV compatible television does not improve the quality of the Standard Definition Television.
LCD TV manufacturers adopt the 16:9 aspect ratio that is compatible for HD Ready 1080p video standard, due to the increasing scale of manufacturing yield and the resolution of the VRAM and VGA that is 768 pixel format. HDTV display images in higher details than the DVD or analog television as it comes with double the linear resolution of SDTV(Standard Definition Television). A high resolution requires higher bandwidth to be transmitted in correct form.
A television or a radio receives signals through various media such as a satellite, cable or air medium and this signal is converted to the form the device is capable of displaying. This is made possible with the digital tuners. A tuner is a device that configures a device, no matter if it is an electronic device, mechanical device or a musical device. Tuners convert low frequency radio frequency signals to a form that is supported by the device. A tuner is also capable of receiving digital broadcasts through the satellite or any other medium and displaying it on the standard definition television or high definition television sets.
Sources of HD Signal Broadcast
HDTV require High Definition signals to display superior quality images. High Definition signals are broadcast by various sources such as:
1.Some internet connections such as Apple TV can broadcast HD signal for video games like Playstation 3 and Xbox 360. Some other services also offer movie trailers, HD movies, clips to download and more.
2.Satellite based TV companies such as Freesat and Sky digital offer HDTV. To receive HD content new satellite dish and New satellite receiver box are required.
3.Blu-ray disc can store up to 10 hours of HD video content based on the encoder settings.
4.HD signals are broadcast over the air and hence can be captured by the antenna. An HD tuner is required to receive this signal. Some HDTV models come with built-in HD tuner and other that do not have this facility would require a HD tuner box, which can be rented from a satellite company or a cable company.
5.Some computer graphics card either have DVI or HDMI interfaces to display images or video to an HDTV.
6.Some DVD-R disc provide 20 to 40 minutes of HD video content.
Parameters of HDTV
Three major parameters of HDTV broadcast systems are Scanning system, Frame rate and Frame size. Scanning system is identified with the letter ‘i’ for interlaced scanning and ‘p’ for progressive scanning. Frame rate is defined as the number of video frames that are produced per second. Frame size is defined as the number of pixels that are formed both horizontally and vertically. For example, 1920 x 1080. Whenever these parameters are used, it may be specified in the form as frame size scanning system frame rate. Frame rate can also specified without a resolution. In the case of a resolution, both the transmitted signal and the native resolution of the TV is considered. HDTV sets upconvert or upscale the transmitted signal to the native format. The video format resolution of high definition display is usually of 720 horizontal lines. The native resolution of HD Ready TV is 1366 x 768 pixels.
Advantages
Images that are formed in HDTV are of better quality as it has more number of lines of resolution. As the gaps between the scan lines are narrower, the images produced are more sharper. Sound track of HDTV video signal is Dolby Digital 5.1 surround sound that produces excellent surround sound capability.
Disadvantages
The best quality of HDTV is not achieved as the operators do not follow HDTV specification properly. They use lower resolutions and broadcast more channels with limited bandwidth. This reduces the quality of the video that is broadcast. Inappropriate cabling is also a factor that puts down the quality of the image. HDMI cables are more expensive than the component cables but provide best picture and sound quality. Though HDTV has some disadvantages one must consider its plus points and deal with this concept accordingly.
Samsung PS50C96HD 50 inch Plasma TV
January 15, 2008
Plasma TVs have become the rage of this generation, with larger than life images, perfect clarity and bass sound to enliven the surroundings. Samsung
PS50C96HD 50 inch Plasma TV is a 50 inches Digital Television Certification HD ready gadget, manufactured to give perfect picture broadcasts.
The video interface is VGA (HD-15), HDCP compatible with black enclosure and PDP Plasma technology. Resolution of 1366 x 768 pixels assures clear picture and the display format of 720p accentuates the clarity. Image Aspect Ratio is 16:9, Dynamic contrast ratio is 15000:1 and brightness is 1300 cd per metre square. The bright clear pictures are a pleasure to watch whether for information or entertainment.
Video interface is component, Composite, HDMI, S-Video and Scart while the progressive scanning for line doubling is possible in this device. Wide screen mode for conventional plasma TV is 4:3 and Zoom is 16:9. Vertical viewing angle is 175 degrees and with the 3D digital comb filter, the quality of display surpasses the common TV.
Samsung PS50C96HD Plasma TV has colour temperature controls like warm1, warm2, Normal, Cool1 and Cool2. The picture adjustments can be varied as the interests with Custom, Standard, Music, Film and Speech modes supported by this plasma TV.
Other features of this chic 50 inch plasma TV
• Video noise reduction
• Auto power off
• Parental control
• On-screen menu
• Dynamic contrast
• Digital Natural Image engine
• Filter Bright
• Game mode
• TV tuner
• Teletext
• Freeze memo
• Parental Channel lock
• Closed Caption Capability
• Universal infra-red remote control
Multi channel preview with Picture in Picture feature, Stereo reception System of NICAM and A2 and input formats of 480p, 720p, 1080i, 480i, 576i and 576p with supported computer resolutions of 1024 x 768 (XGA), 640 x 480 (VGA), 800 x 600 (SVGA), 640 x 350 and 720 x 400 adds charm to this unique TV.
Supported devices like VCR, Satellite TV system, Cable box, DVD player, and audio system with stereo sound output mode, built-in surround mode, SRS TruSurround XT sound effects, Audio controls with 5 band equalisers and balance and 2 speakers are smart additions.
Samsung PS50C96HD 50 inch Plasma TV needs a 20 Watts total output power, and the features like auto volume adjustment and balance control, 2 x right/left channel speakers that are built-in and require 10 Watts are remarkable. Cable card slot provided are supported by the built-in stand with table top design and swivel stand feature. Flat panel mount interface is 600 x 400 mm requiring power of AC 230 V or 50/60 Hz. Power consumption for stand-by and sleep is 1 Watt. All these features are infused in the unique appliance with dimensions of 123 cm x 9.5 cm x 78.9 cm and the TV weighs just 41.6 kilograms.
PLASMA TV BUYING GUIDE
September 7, 2006
The advent of digital broadcasting and other technological advances has pushed TV entertainment to higher levels of viewing pleasure for consumers. Initiatives to turn to digital broadcasting have become increasingly popular, even institutionalized by government authorities in some countries. Thus emerged digital television (DTV), high definition television (HDTV), Digital Versatile Disk (DVD-Video), computer video, and digital satellite broadcasts.
What is a Plasma TV?
Plasma TV is usually associated with those ultra-thin, space-saving TV displays that can be hung on walls. But there is more to Plasma TV than their ultra-thin figures. Wikipedia defines plasma display as “ an emissive flat panel display where light is created by phosphors excited by a plasma discharge between two flat panels of glass. Simply put, the plasma display is composed of separate glass compartments or cells that infused with neon-xenon gas suspended in plasma. Once electrically charged, the gases emit green, red and blue phosphors, forming what is called as pixels. This element basically gives Plasma TV brighter display and wide color range.
Plasma TV Buying Tips
There is a plethora of choices available when shops around for plasma television that is just right for your home. But it would be a good idea if one knows the right specifications and features to look for in a Plasma TV. Here are some basic tips on buying plasma television.
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- First of all, survey the room where the Plasma TV is to be placed in. Consider the size of the room before you choose your Plasma TV. Remember that plasma displays are usually larger than your usual LCDs, with largest sizes up to 71 inches diagonally. New models may churn out larger sizes, but generally plasma TV offers the largest option in terms of size. Considering the size, it necessarily follows that the plasma TV youve been eyeing must fit in your room. Color and graphical flaws are more obvious up front; so observe the right viewing space away from the TV screen. The basic rule is to sit at a distance 1.5 to three times the screen width away.
- A Plasma TV can be mounted on a wall and you can have the best video art there is. But before you do, make sure that the wall can absorb the TVs weight. While they are relatively lighter than other types, Plasma TVs can weigh up to 30 kgs.
- Check out the brightness feature. Remember that brightness or luminance refers to the brightness of a screen, and is expressed in cd/m2, 2000cd/m2 for example. The higher the number, the more luminous the wide TV screen. So take note and consider the brightness feature, especially if you intend to place it in a dimly lighted or brightly lighted space.
- Usually expressed in ratio, the Contrast feature of a TV screen refers to its capability to display the colors black and white. The contrast ratio refers to the graduation of shades of color gray that the TV is capable of displaying. It determines the quality of detail that can be seen when dark scenes are displayed.
There are many other features that one must consider before buying a plasma television. But to get the right one for you, stick to the basic rule of thumb know what you are buying.
