BLOCK DIAGRAM OF LCD TELEVISION RECEIVER
The tuner can receive both VHF and UHF. The IF signal IC contains IF circuits for video and sound, synchronizing signal separators, AFC (automatic frequency control) circuits, and AGC (automatic gain control) circuits. It consumes about 150mW.
The chroma signal IC contains a color demodulator and RGB video-generating circuits and consumes about 250 mW. Since the liquid crystal is driven by AC, polarities of the video signal for red, green, and blue are reversed by the AC video signal generating circuit. The liquid crystal panel made of red, green, and blue colors arranged in a mosaic pattern changes colors a each horizontal scanning period.
Thus it is necessary to change video signals to red, green, and blue for each period of horizontal scanning. This is done by the RGB switching circuit. The synchronization control circuit includes a PLL (phase locked loop) circuit which performs phase- phase-phase-synchronisation among input synchronization signal, X and Y driving signals. The panel substrates have two ICs for the X side drive and two ICs for the Y side drive.
The X-driving IC is composed of the shift register which determines the column direction of TFT and the transfer gates which select R, G, or B connected to the shift register. In the column direction of the TFT array, upper and lower drive ICs are alternately connected.
The YIC is a shift register that determines the direction of the IFT array and TFT and right and left drive ICs are connected alternately.
BLOCK DIAGRAM OF DIGITAL TV TRANSMITTER
A particular television program's video and audio signals are converted into digital by using analog-to-digital converters (ADCs) These digitally converted video and audio signals are compressed to reduce the data required to limited bandwidth.
Various compression techniques are available for video data but MPEG-2 is widely used as it achieves a high compression rate by storing only the changes from one frame to another, instead of each entire frame. Whereas AC-3 is used for audio compression as it is faithful to encode up to 6 discrete channels (such as home theatre left, right, center, left-rear, right-rear, and sub-woofer speakers).
Similarly, hundreds of TV programs are digitally compressed individually and multiplexed together using a multiplexer. The FEC encoder takes preventive measures to protect the transport streams from errors caused by noise and interference in the transmission channel. This involves QAM or OFDM.
The final stage is the upper converter, which converts the modulated digital signal into the appropriate RF channel of higher frequency for suitable transmission towards the satellite.
SMART TV
Definition: A smart TV is any TV that has built-in Internet connectivity, allowing it to access a range of online services including video on demand, social networking, and instant messaging (YouTube, Facebook, Twitter, Google, etc.,).
In order to access the extra features offered by a smart TV you'll need some sort of Internet connection at home. Some models are also capable of accessing Wi-Fi, either using built-in hardware or a USB dongle that plugs into the back (usually an optional extra).
Smart TVs either have an Ethernet port or Wi-Fi capability so we can stay connected to the Internet. Like computers and smartphones, they come with an operating (OS) to run widgets and apps so they can do what an internet-connected TV is supposed to do: stream videos and music.
FEATURES OF SMART TV
1. Internet Feature: Smart TV has built-in Internet connectivity with the fully featured web browser which allows access to most like YouTube, Facebook, Twitter, Google, Gmail, Yahoo, etc.
2. High Quality Crystal Clear Pictures: Ultra HD Smart TV produces over 8 million pixels which results in crystal-clear pictures.
3. Miracast Feature: Miracast is a wireless display standard designed for wirelessly connecting our smartphone, tablet, or PC's screen to a television without requiring any physical HDMI cables (High definition multimedia interface, is used to transmit both audio and video digital data) and watch our child's birthday video on a big screen.
4. Sharing Photos and Videos: Share photos, videos, and more on this smart TV from your smartphone, tablet, or laptop.
5. High Resolution Videos: Watch movies and videos with 4K ultra HD smart TV which produces images at a resolution of 3840-2160 pixels.
6. 4X Graphics Engine: The 4X graphics engine makes your favorite games look more spectacular (Adbhutamania).
7. Advanced Image-Quality Enhancement Technology: Advanced image-quality enhancement technology adjusts and repairs any deviations in color, so all displayed hues will be vibrant.
8. Experience dbx Surround Sound: The dbx-TV feature makes. smart TV produces a rich, deep, and digital quality 10.1 channel sound.
9. High Aspect Ratio: The aspect ratio of smart TV is 16:9.
NEED IN SATELLITE TV BROADCASTING OVER WIDE AREA
High power, highly directive land-based transmitters transmit wide b and microwave signals to the geostationary satellite above the transmitter. Each microwave channel has a bandwidth of several tens of megahertz and can accommodate many TV signals and thousands of telephone channels (or) a suitable combination of these.
Frequency modulation is used for both 'up channel and 'down channel' transmission. FM., though it needs a larger bandwidth, offers good immunity from interference and requires less power in the satellite transmitter.
A special antenna to receive the signals and a frontend converter unit to modify the signals into conventional broadcast standards A high-power satellite ATS-6 (Application Technology satellite) is positioned at a height of 36,000 km in a geostationary synchronous orbit with a sub-satellite longitude of 33°. East was used for beaming TV programs over most parts of the country. TV programs from the earth station at Ahmedabad were transmitted to ATS-6 at 6Hz FM carrier with the help of a 14m parabolic dish antenna. It is a satellite communication. The FM carrier had a bandwidth of 40MHz. The down transmission' from the satellite was done from an 80 W FM transmitter at 86 MHz. The transmitted signal consisted of a video band of 5MHz and two audio signal frequencies modulated on two audio subscribers of 5.5 MHz and 6 MHz.
