HDTV Tuner - High definition television Tuner
HDTV stands for high definition television, a new means of broadcasting and the machines that take advantage of it. HDTV broadcasts video digitally, in contrast to the common analog formats like PAL, NTSC, and SECAM.HDTV is defined as having 1080 active pixel lines and a screen with a length-to-height ratio of 16:9. This screen shape departs from the conventional ratio of 4:3. The new ratio lends itself better to widescreen movies. HDTV resolution is about twice as high as typical CRT sets, which have 480 active pixel lines instead of 1080. The increase in resolution is just one of the benefits of HDTV. Because the image is digital rather than analog, it tends to be much sharper on televisions of all sizes.
HDTV tuner is commonly known as ATSC tuner also. It allows reception of digital television signals broadcast over-the-air by TV stations. Such tuners may be incorporated into the televisions, VCRs, digital video recorders, and descramblers which provide audio/video output-connectors of various types.
The terms like HDTV tuner and receiver are used freely and frequently. The tuner generates the audio and video signals needed for television and performs the tasks like demodulation, error correction, transport stream demultiplexing, decompression, analog to digital conversion, AV synchronization, and media reformatting which includes interlace to progressive scan or vice versa, picture resolutions, aspect ratio conversions, frame rate conversion, even scaling. It is commonly used to convert a low-resolution picture to a high-resolution display. HDTV tuner functions by generating audio and video signals that are picked up from over the air TV broadcasts. These tuners provide the functions like:
Demodulation: it means the signal that is pulled off the airways is transformed into a usable signal that your TV set can use to display quality images and quality sound.
Transport stream demultiplexing: multiple digital signals are combined and then transmitted from one antenna source to create over the air broadcasts. HDTV tuner is able to decode the transport stream and display it on your TV set properly.
Decompression: digital signals that are broadcasted over the air are compressed, once they are received by the HDTV tuner, these compressed packets of digital data are then restored to their original size and properties, this saves signal loss and the quality of the signal is maintained throughout the procedure.
Error correction: It is a technology used by the HDTV tuner to make sure that any data that is missing should be corrected. Sometimes interference or a poor quality signal will cause the loss of data information that the HDTV tuner receives, with the help of error correction technology, the HDTV tuner has the ability to perform a number of checks and repair data so that a signal can be properly viewed on a particular TV set.
Analog to digital conversion: it is sometimes called ADC or A to D conversion, this refers to a technology in which an analog signal is converted into digital signals. In the perspective of HDTV tuner, an analog TV broadcast that is broadcasted over the air is received by the HDTV tuner and converted to a new digital signal that can be viewed on a HD TV set.
AV synchronization: it is usually the coordination of audio and video signals being displayed on your digital TV in proper time and sequence. AV synchronization process makes sure that your audio sound doesn’t lag behind or runs before the video that is being displayed on your TV set or vice versa. This technology makes sure that both your audio and video are in synchronization mode.
Media reformatting: It is extremely important and delicate process because different TV sets format their images significantly different and can use several different technologies. A HD TV has a progressive scan picture. With progressive scan, the entire image is refreshed 30 times per second. HD TV’s can come in different aspect ratios (shape of the TV screen). HD TV’s come in aspect ratios more in the shape of a 16:9 rectangle.
As soon as you shift to HDTV, you may need to obtain various appliances with one function or the other in order to give the best viewing and experience a most near perfect situation.
Among these appliances is the AV Tuner which is very useful both in an HDTV setup. Most consumers have put it into use. These appliances make shifting from one audio or video sources to another very easy. Some of the leading and best selling A/V selector switches/ Tuners available in the market include;
The Sima VS
It can be positioned anywhere due to its compact design and selecting a source is very easy. All that need to be done is a touch of a button. It’s Specifications include 1 HDMI output and 3 HDMI inputs, Signal Enhancement, Compact and light remote control and AC adaptor.
The JVC JX
Its Specifications are 1 input with stereo audio jacks and component video. 1 output with composite video, 5 – video and stereo audio jacks. 2 inputs with composite video, 5 – video and stereo audio jacks, 3 inputs with audio jacks and component video, 1 year parts warranty.
Beside these many others are also available in the market with more advanced features.