How do wifi televisions work

The beam paints one line across the screen from left to right. It then quickly flies back to the left side, moves down slightly and paints another horizontal line, and so on down the screen. In this figure, the blue lines represent lines that the electron beam is "painting" on the screen from left to right, while the red dashed lines represent the beam flying back to the left.

When the beam reaches the right side of the bottom line, it has to move back to the upper left corner of the screen, as represented by the green line in the figure.

When the beam is "painting," it is on, and when it is flying back, it is off so that it does not leave a trail on the screen. The term horizontal retrace is used to refer to the beam moving back to the left at the end of each line, while the term vertical retrace refers to its movement from bottom to top. As the beam paints each line from left to right, the intensity of the beam is changed to create different shades of black, gray and white across the screen.

Because the lines are spaced very closely together, your brain integrates them into a single image. A TV screen normally has about lines visible from top to bottom. In the next section, you'll find out how the TV "paints" these lines on the screen. Standard TVs use an interlacing technique when painting the screen. In this technique, the screen is painted 60 times per second but only half of the lines are painted per frame. The beam paints every other line as it moves down the screen -- for example, every odd-numbered line.

Then, the next time it moves down the screen it paints the even-numbered lines, alternating back and forth between even-numbered and odd-numbered lines on each pass. The entire screen, in two passes, is painted 30 times every second. The alternative to interlacing is called progressive scanning , which paints every line on the screen 60 times per second. Most computer monitors use progressive scanning because it significantly reduces flicker.

Because the electron beam is painting all lines 30 times per second, it paints a total of 15, lines per second. Some people can actually hear this frequency as a very high-pitched sound emitted when the television is on. When a television station wants to broadcast a signal to your TV, or when your VCR wants to display the movie on a video tape on your TV, the signal needs to mesh with the electronics controlling the beam so that the TV can accurately paint the picture that the TV station or VCR sends.

A signal that contains all three of these components -- intensity information, horizontal-retrace signals, and vertical-retrace signals -- is called a composite video signal. One line of a typical composite video signal looks something like the image on this page. The horizontal-retrace signals are 5-microsecond abbreviated as "us" in the figure pulses at zero volts.

Electronics inside the TV can detect these pulses and use them to trigger the beam's horizontal retrace. The actual signal for the line is a varying wave between 0. This signal drives the intensity circuit for the electron beam. In a black-and-white TV, this signal can consume about 3.

A vertical-retrace pulse is similar to a horizontal-retrace pulse but is to microseconds long. The vertical-retrace pulse is serrated with horizontal-retrace pulses in order to keep the horizontal-retrace circuit in the TV synchronized. When a color TV needs to create a red dot, it fires the red beam at the red phosphor. Similarly for green and blue dots. To create a white dot, red, green and blue beams are fired simultaneously -- the three colors mix together to create white. To create a black dot, all three beams are turned off as they scan past the dot.

All other colors on a TV screen are combinations of red, green and blue. A color TV signal starts off looking just like a black-and-white signal. An extra chrominance signal is added by superimposing a 3.

Right after the horizontal sync pulse, eight cycles of a 3. Following these eight cycles, a phase shift in the chrominance signal indicates the color to display. The amplitude of the signal determines the saturation. Here is the relationship between color and phase:. A black-and-white TV filters out and ignores the chrominance signal.

A color TV picks it out of the signal and decodes it, along with the normal intensity signal, to determine how to modulate the three color beams. Now you are familiar with a standard composite video signal. Note that we have not mentioned sound. If your VCR has a yellow composite-video jack, you've probably noticed that there are separate sound jacks right next to it.

Sound and video are completely separate in an analog TV. The first four signals use standard NTSC analog waveforms as described in the previous sections.

As a starting point, let's look at how normal broadcast signals arrive at your house. A typical TV signal as described above requires 4 MHz of bandwidth. If you do run into a frozen screen or hanging process, powering the TV off and on will usually resolve the problem.

Smart TVs do offer other potential advantages. The newest sets have added popular voice assistants to the mix. Voice search now lets you find content from live TV as well as streaming services, and adds search for everything from weather and stock prices to looking up the latest celebrity gossip. The voice integration lets you access other services from your couch, letting you order a pizza or summon an Uber in comfort.

And if you don't like the TV's built-in voice assistant, you can usually pair it with the smart speaker of your choice. These new features also let you control smart home devices like connected lights and thermostats, view feeds from your Nest camera or Ring doorbell , or control your robot vacuum. As voice assistants continue to evolve, you can expect to see the same improvements come to current smart TVs via software and firmware updates.

Because these TVs tend to have beefier processors than regular sets, as well as online connections, manufacturers can add other features, such as casual games, which are now quite common on smart sets. The games are nowhere near as sophisticated or as compelling as those available on a PlayStation or Xbox console, but they can be addictive. Many sets also let you mirror or share pictures and video from a connected smartphone on their big screens. Most manufacturers rely on proprietary apps to offer a more curated experience when sharing media, while others rely on third-party solutions like Google Chromecast.

In either case, sharing the videos and photos from your phone or tablet has never been easier. A new trend in smart TVs is vastly improved built-in sound systems. LG and Sony are making particular advances in this area, offering Dolby Atmos sound on several models and hoping that the smart TV will also do duty as the home stereo system to stream music and online radio stations.

The biggest trend in smart home technology is the smart speaker , a speaker with built in microphone and hardware to run a voice-enabled assistant. Amazon made the first big splash here with the Amazon Echo and other Alexa-enabled devices , but Google's own Google Assistant has made strides in products like the Google Home.

And Apple's HomePod puts Siri into a similar form factor. The great news is that these devices will usually work with most smart TVs, and compatibility is improving all the time as new software updates add capability to existing smart TVs.

As it stands, all of the major TV manufacturers have smart speaker compatibility with at least one of the three main smart assistant platforms Amazon, Apple and Google.

These options often require using an additional device , such as a smart speaker or mobile device, but it will give you a way to control your TV and smart devices with the convenience of simple speech.

Many of the smart TVs on the market now have these voice assistants built in. These models generally offer remote controls that feature built in microphones, letting you press a button to activate voice interaction. When enabled, they let you simply speak to the room, and the TV will listen for your commands. The leading models are from Amazon, Apple, Google and Roku.

But, it's worth noting that these streaming devices rarely offer more functionality than current smart TVs will provide. In fact, all of the device manufacturers we just mentioned have the same interface and app selections available in their respective smart TVs.

Those include nearly every major service, as well as hundreds of more obscure channels, ranging from Kung-Fu Theater to Victory Westerns. In fact, Roku offers more options than any other set-top box or any smart TV on the market.

So if you don't need to buy a new TV but do want smart-TV services, a separate, inexpensive streaming-media player is the prudent choice. In addition, set top-boxes, such as the Roku Ultra , offer 4K content. If you live in an Apple household and want your iTunes collection on the big screen, you'll need an Apple TV , which is the only device that can deliver that iTunes connection. No smart TVs have apps for iTunes. However, it does not offer 4K Ultra HD support and has a limited number of streaming services.

The Fire TV Stick is even more affordable. A smart TV costs more than a comparable set that lacks smart services. However, that price difference is quickly evaporating, and soon most sets will have smart services built in. In , it's hard to even find a 4K TV that doesn't have smart capabilities and internet connectivity.

The price difference can also be deceiving, because higher-end TVs often offer more than just connected services. Usually, smart TVs also include better video processing — in other words, better picture quality — and expanded features, such as more HDMI ports on the back. That means you get more for your money than just an internet connection and apps. In theory, the answer is clearly yes. So-called white-hat hackers have brought attention to the issue by demonstrating ways to break into a smart TV connected to the internet and do things like steal passwords and change channels.

Many who are putting televisions on walls and other such locations have no way of hiding wires other than to run them behind the walls, which can make for a difficult installation. Wireless television makes this entire process substantially easier.

Currently, there are only certain high definition sets capable of receiving a wireless television signal. Therefore, those who want to take advantage of the technology will likely need to buy a new set specifically set up for that purpose.

While it may be possible to hook up a receiver to a television without wireless technology, the final connection to the TV will still require wires. You should also change the Service Set Identifier SSID , which is your network name, to something other than the default so that hackers can't immediately tell what router you are using. And selecting a strong password never hurts. Wireless networks are easy and inexpensive to set up, and most routers' web interfaces are virtually self-explanatory.

For more information on setting up and using a wireless network, check out the links that follow. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar.

Mobile Newsletter chat subscribe. How WiFi Works. Wireless networks make it easy to connect to the internet wherever you go. Contents What Is WiFi? What Is WiFi? Here's what happens: A computer's wireless adapter translates data into a radio signal and transmits it using an antenna. A wireless router receives the signal and decodes it. The router sends the information to the internet using a physical, wired ethernet connection.

They transmit at frequencies of 2. This frequency is considerably higher than the frequencies used for cell phones, walkie-talkies and televisions.

The higher frequency allows the signal to carry more data. The 2. In ideal conditions, the 5 GHz band has a max range of about feet 61 meters , but in the real world, it is much more prone to interference from walls, doors and other objects.

For a while, its cost made it popular, but now it's less common as faster standards become less expensive. It can handle up to 11 megabits of data per second, and it uses complementary code keying CCK modulation to improve speeds. It uses orthogonal frequency-division multiplexing OFDM , a more efficient coding technique that splits that radio signal into several sub-signals before they reach a receiver.

This greatly reduces interference. It significantly improved speed and range over its predecessors. For instance, although It is less prone to interference and far faster than its predecessors, pushing a maximum of megabits per second on a single stream, although real-world speeds may be lower. Like It is sometimes called 5G because of its frequency band, sometimes Gigabit WiFi because of its potential to exceed a gigabit per second on multiple streams and sometimes Very High Throughput VHT for the same reason.

This standard extends the capabilities of First of all, the new routers allow an even higher data flow rate, up to 9. WiFi 6 also lets manufacturers install many more antennas on one router, accepting multiple connections at once without any worry of interference and slowdown. Some new devices also connect on a higher 6 GHz band, which is about 20 percent faster than 5GHz in ideal conditions.

WiFi Hot Spots " ". WiFi has enabled people to work anywhere they can get a signal, like at this coffee shop. Building a Wireless Network " ".