How Digital Television Works? To know how analog TV works | Soukacatv.com

If you've looked at television sets at any of the big electronics retailers in the United States lately, you know that digital TV, or DTV, is a big deal right now. Most stores have whole areas devoted to digital TV sets. You're also hearing a lot about four other topics:

·         HDTV and HDTV broadcasts

·         Digital satellite services

·         Digital cable

·         DVDs and DVD players

Unless you are among the people in the United States who have purchased a DTV set, what you have in your living room is a normal analog TV that seems to be working just fine despite all the hype. ­Most people, faced with this level of product proliferation, can only ask, "What the heck is going on here?!"

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On June 12, 2009, television stations in the United States completed the transition from analog to digital broadcasting. Consumers receiving local television signals over analog antennas now must use converter boxes to receive programming on their TVs. This deadline was pushed back several times in the last few years because of both broadcasters' and consumers' inability to meet the FCC's criteria for a successful transition to digital broadcasting.

The change was last scheduled to take place on Feb. 17, 2009, but was pushed back one final time to allow more people to purchase new TVs or converter boxes to allow them to make the transition. Some stations, however, switched to digital broadcasting in February 2009 anyhow because they'd already contracted time to broadcast on digital transmitters and staying analog would require a costly budgetary adjustment.

In this article, we will explore the world of digital television so that you can understand exactly what is going on in this medium.

Understanding Analog TV

To understand digital TV, it's helpful to understand analog TV so that you can see the differences. (If you've read How Television Works, then you know how analog TV works).

The analog TV standard has been in use in the United States for about 50 years. To review quickly, here are the basics of analog television transmission:

·         A video camera takes a picture of a scene. It does this at a frame rate of 30 frames per second.

·         The camera rasterizes the scene. That is, the camera turns the picture into rows of individual dots called pixels. Each pixel is assigned a color and intensity.

·         The rows of pixels are combined with synchronization signals, called horizontal sync and vertical sync signals, so that the electronics inside a TV set will know how to display the rows of pixels.

This final signal, containing the color and intensity of each pixel in a set of rows, along with horizontal and vertical sync signals, is called a composite video signal. Sound is completely separate. When you look on the back of your VCR and you see the yellow plug, that's the plug for composite video. Sound is either a white plug (on VCRs that do not handle stereo sound) or a red plug and a white plug (on VCRs that do handle stereo).

There are lots of different things you can do with a composite video signal and a sound signal. Here are just a few:

·         You can broadcast them as radio waves. When you attach an antenna to your TV set and pick up local stations for free, you're receiving broadcast television from local TV stations.

·         You can record them with a VCR.

·         You can transmit them through a cable TV system along with hundreds of other composite signals.

Many different kinds of equipment understand composite video signals.

When a composite video signal is broadcast over the airwaves by a TV station, it happens on a specific frequency. In the United States, we know these frequencies as VHF channels 2 through 13 and UHF channels 14 through 83.

The composite video signal is transmitted as an AM signal and the sound as an FM signal on these channels. See How TV Works for details on transmission, and How Radio Works for details on AM and FM. The FCC allocated three bands of frequencies in the radio spectrum, chopped into 6-MHz slices, to accommodate these TV channels:

·         54 to 88 MHz for Channels 2 to 6

·         174 to 216 MHz for Channels 7 through 13

·         470 to 890 MHz for UHF Channels 14 through 83

When your VCR wants to display its signal on a normal analog TV, it takes the composite video signal and the sound signal off the tape and then modulates those signals onto a 60-MHz (channel 3) or 66-MHz (channel 4) carrier, just like a TV station would. Instead of broadcasting it, however, the VCR sends it straight to the TV. A cable box or satellite box does the same thing.

Right now you hear a lot about "digital satellite systems" and "digital cable systems." The set-top box receives a digital signal from the satellite or cable; the box then converts that signal to an analog signal and sends it to your analog TV. That's why if you're a digital cable or satellite TV subscriber, your provider probably told you that the June 2009 DTV transition wouldn't require you to buy new equipment.

True digital TV, on the other hand, is completely digital and involves:

·         Digital cameras working at a much higher resolution than analog cameras

·         Digital transmission

·         Digital display at a much higher resolution

You can see the difference in resolution in the next section.

What's Wrong with Analog TV?

If you currently have an analog TV, and it works fine with broadcast TV, cable TV, VCRs, satellite TV, camcordersand so on, an obvious question would be, "What's wrong with analog TV?"

The main problem is resolution.

·         The resolution of the TV controls the crispness and detail in the picture you see.

·         The resolution is determined by the number of pixels on the screen.

·         An analog TV set can display 525 horizontal lines of resolution every 30th of a second. In reality, however, an analog TV displays half of those lines in a 60th of a second, and then displays the other half in the next 60th, so the whole frame is updated every 30th of a second. This process is called interlacing.

That's been the way TV works for years. But now we've used to looking at computer monitors and expect much better resolution. The lowest-resolution computer monitor displays 640 x 480 pixels. Because of the interlacing, the effective resolution of a TV screen is perhaps 512 x 400 pixels.

So the worst computer monitors you can buy have more resolution than the best analog TV set; and the best computer monitors are able to display up to 10 times more pixels than that TV set. There is simply no comparison between a computer monitor and an analog TV in terms of detail, crispness, image stability and color. If you look at a computer monitor all day at work, and then go home and look at a TV set, the TV set can look very fuzzy.

The drive toward digital TV is fueled by the desire to give TV the same crispness and detail as a computer screen. If you have ever looked at a true digital TV signal displayed on a good digital TV set, you can certainly understand why -- the digital version of TV looks fantastic! There's no comparison. With 10 times more pixels on the screen, all displayed with digital precision, the picture is incredibly detailed and stable.

It's hard to convey the difference between a DTV signal and an analog signal without an actual demonstration, but here's a static comparison that can help you understand the idea. Below is a picture of an odometer:

This is a nice, crisp picture. Let's assume that this picture is being displayed on a good digital TV so that this is what you actually see. The following photo shows you what you would see on an analog TV:

You can see that the analog TV picture is much fuzzier than the digital TV image. Look, for example, at the teeth on the gears. There's a significant difference in picture quality that's even more obvious when the image is moving. It is that quantitative difference that drives the interest in digital TV. And as if the incredible picture weren't enough, digital TV also offers much better sound.

TV Goes Digital

The term "digital TV" is used in many different ways right now, depending on whom you're talking to. There's also the term "HDTV," which is the most advanced form of digital TV in use in the United States. The reason it gets confusing is because digital TV in the United States combines three different ideas.

The first idea that is new to digital TV is the digital signal.

Analog TV started as a broadcast medium. TV stations set up antennas and broadcast radio signals to individual communities. You can attach an antenna to your TV and pick up channels 2 through 83 for free. What you receive, as described earlier, is a single, analog composite video signal and a separate sound signal.

Digital TV started as a free broadcast medium as well. For example, in San Jose, Calif., you can tune in to about a dozen different commercial digital TV stations if you have a digital TV receiver and an antenna. The FCC gave television broadcasters a new frequency to use for their digital broadcasts, so until the digital transition is complete, each broadcaster has an analog TV channel and a digital TV channel. The digital channel carries a 19.39-megabit-per-second stream of digital data that your digital TV receives and decodes.

Each broadcaster has one digital TV channel, but one channel can carry multiple sub-channels if the broadcaster chooses that option. Here's how it works:

On its digital channel, each broadcaster sends a 19.39-megabit-per-second (Mbps) stream of digital data. Broadcasters have the ability to use this stream in several different ways. For example:

·         A broadcaster can send a single program at 19.39 Mbps.

·         A broadcaster can divide the channel into several different streams (perhaps four streams of 4.85 Mbps each). These streams are called sub-channels, and this type of broadcasting is called multicasting. For example, if the digital TV channel is channel 53, then 53.1, 53.2 and 53.3 could be three sub-channels on that channel. Each sub-channel can carry a different program.

The reason that broadcasters can create sub-channels is because digital TV standards allow several different formats. Broadcasters can choose between three formats:

·         480i - The picture is 704x480 pixels, sent at 60 interlaced frames per second (30 complete frames per second).

·         480p - The picture is 704x480 pixels, sent at 60 complete frames per second.

·         720p - The picture is 1280x720 pixels, sent at 60 complete frames per second.

·         1080i - The picture is 1920x1080 pixels, sent at 60 interlaced frames per second (30 complete frames per second).

·         1080p - The picture is 1920x1080 pixels, sent at 60 complete frames per second.

(The "p" and "i" designations stand for "progressive" and "interlaced." In a progressive format, the full picture updates every 60th of a second. In an interlaced format, half of the picture updates every 60th of a second.)

The 480p and 480i formats are called the SD (standard definition) formats, and 480i is roughly equivalent to a normal analog TV picture. When analog TV shows are upconverted and broadcast on digital TV stations, they're broadcast in 480p or 480i.

The 720p, 1080i and 1080p formats are HD (high definition) formats. When you hear about "HDTV," this is what is being discussed -- a digital signal in the 720p, 1080i or 1080p format.

Finally, the HD formats of digital TV have a different aspect ratio than analog TVs. An analog TV has a 4:3 aspect ratio, meaning that the screen is 4 units wide and 3 units high. For example, a "25-inch diagonal" analog TV is 15 inches high and 20 inches wide. The HD format for digital TV has a 16:9 aspect ratio, as shown below:

The type of signal, format and aspect ratio have all changed in the process of converting from analog TV to digital TV in the United States.

Digital Compression

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The idea of sending multiple programs within the 19.39-Mbps stream is unique to digital TV and is made possible by the digital compression system being used. To compress the image for transmission, broadcasters use MPEG-2 compression, and MPEG-2 allows you to pick both the screen size and bit rate when encoding the show. A broadcaster can choose a variety of bit rates within any of the three resolutions.

You see MPEG-2 all the time on the Web on Web sites that offer streaming video. For example, if you go to iFilm.com, you will find that you can view streaming video at 56 kilobits per second (Kbps), 200 Kbps or 500 Kbps. MPEG-2 allows a technician to pick any bit rate and resolution when encoding a file.

There are many variables that determine how the picture will look at a given bit rate. For example:

·         If a station wants to broadcast a sporting event (where there is lots of movement in the scene) at 1080i, the entire 19.39 megabits per second is needed to get a high-quality image.

·         On the other hand, a newscast showing a newscaster's head can use a much lower bit rate. A broadcaster might transmit the newscast at 480p resolution and a 3-Mbps bit rate, leaving 16.39 Mbps of space for other sub-channels.

It's very likely that broadcasters will send three or four sub-channels during the day and then switch to a single high-quality show that consumes the entire 19.39 Mbps at night. Some broadcasters are also experimenting with 1- or 2-Mbps data channels that send information and Web pages along with a show to provide additional information.

Buying a Digital TV Set

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If you go to an electronics store today to buy a new TV set, there are four types of sets that you will see on the shelf:

·         Analog TV sets

·         Digital-ready sets - They should be identified as standard definition (SDTV) sets. These TVs are normally 480p displays with a digital tuner built in. The problem with these sets is that their maximum resolution is the low 480p SD resolution, so if you want to watch high-definition TV, you won't be able to use these sets.

·         HDTV-ready sets - These sets are essentially monitors able to display 1080i/p resolution in the 16:9 aspect ratio. They may or may not have tuners built in.

·         Integrated HDTV sets - These sets have a digital tuner for broadcast DTV signals integrated into an HDTV display. With the standards changing so much, you may end up paying for an integrated tuner that becomes obsolete.

The preferred way to handle HDTV is to purchase the components separately:

·         A 16:9 HDTV display capable of 720p and 1080i/p resolution

·         A digital receiver

·         An antenna

Since the HDTV display will be the most expensive piece and will likely last 10 years or more, buying the components in this way allows you to change the receiver if you need to. There are currently three types of receivers:

1.     You can purchase a set-top box and a Yagi antenna to receive broadcast HDTV signals.

2.     You can purchase a set-top box and a small satellite dish to receive HDTV signals from a satellite. 

3.     You can purchase a board for your computer that lets you use your hard disk as an HDTV storage device, along with a Yagi antenna, and use it to receive signals on both your computer monitor and your HDTV display.

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Source: electronics.howstuffworks

Digital vs Analog TV comparison | Soukacatv.com

Digital vs Analog? Analog vs Digital? What’s the big deal about the switch in signal to your TV?

There have been no bigger advancements in technology over the last 20 years then what is happening in the television industry. Only 10 or so years ago the price of flat screen TVs were astronomical and were only affordable by wealthy individuals. Fast forward to today’s retail economy and a quality flat screen TV can be found for well under $500. With these new TVs comes the world of high definition that broadcasts sporting events, movies and television shows with a much clearer picture then televisions of the past. With the broadcast of events in high definition (HD) comes the need for a better broadcasting system, this is where digital TV service has come in and revolutionized the cable TV industry.

Let’s take a further look into the Digital vs Analog TV comparison

Advancements in Technology

Up until the past few years, commercial televisions sets have all worked from receiving analog signals. With analog, televisions receive radio frequencies that were sent out from a variety of TV stations. Each TV station emits a frequency that corresponds to a channel number. With this technology analog TV sets received a constant signal to their antenna that would change when they switched channels.

On the other hand, digital signals work much like computers. Instead of using a radio frequency, the digital signal is sent out in a series of 1s and 0s. Any television with a digital tuner will receive this information and will generate the picture and sound onto their TV.

Quality of Programming

Every one of us who are older than 30 can remember their analog signal from when they were young. While some of the higher quality channels came in with good picture quality most of the time, there were many channels that had the snowy or fuzzy look on the TV screen. This problem has to do with the type of signal transmitted from the different stations. With the analog signal the quality of the signal was determined by the strength of the analog signal, the antenna’s proximity to the television station and possible obstructions depending on where your TV was located.  A weak analog signal constituted a poor picture for the viewer.

With the digital signal, things like proximity and obstructions will not have any effect on the picture. With a binary signal, the broadcast is not only higher quality then the analog signal but the picture will not have has any of the graininess of the analog picture. The only problem that a digital picture may get is a momentary freezing of the picture if the signal gets interrupted. While this was more of a problem with the early digital ready TVs, this technology has been improved upon in the last couple of years to almost be non-existent.

High Definition (HD) TVs

One of the main reasons that the analog vs digital programming has become such a discussed technology is the recent availability of HD TVs to the general population. Sporting events, movies and cable shows show the true value of digital programming as their HD channels are a clear upgrade from “regular” cable channels. From their initial release to present day the pricing of high definition televisions has dropped tremendously. For instance a 32” TV may have costs $2,000 dollars in 2003 and now the same size 32” LED TV with much better features can be found for under $400. With these pricing changes businesses can now afford to add digital ready TVs at low costs.

Overall

Digital vs analog is something that will not even be debated 10 years from now as technology will keep pushing analog technology further and further back.  As of 2013, most satellite TV providers will no longer offer analog channels. With this change more businesses will look to add the LED, commercial grade TVs to their businesses while sending the old analog TVs to the recycle bin.

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products all over the world. For more, please access to https://www.soukacatv.com/.

Source: seniortv

Brief Introduction of Cable Television: Definition, History and Development | Soukacatv.com

Cable television is a way of letting people watch television without having to get signals from an antenna. The television signals are brought to the television through a coaxial cable. People usually have to pay to subscribe to cable television. With cable television, people can watch hundreds of television channels carrying many television shows. Usually some of these are television stations and others are made for the cable companies.

Cable TV is provided by many carriers in across with world. Some of those carriers in the United States are: AT&T U-Verse, CableVision, Comcast, Cox Communications, SuddenLink, Time Warner Cable and Verizon

Another method of subscription television is by Satellite television, especially in places where cable TV is not available.

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Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fiber-optic cables. This contrasts with broadcast television (also known as terrestrial television), in which the television signal is transmitted over the air by radio wavesand received by a television antenna attached to the television; or satellite television, in which the television signal is transmitted by a communications satellite orbiting the Earth and received by a satellite dish on the roof. FM radio programming, high-speed Internet, telephone services, and similar non-television services may also be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation.

A "cable channel" (sometimes known as a "cable network") is a television network available via cable television. When available through satellite television, including direct broadcast satellite providers such as DirecTV, Dish Network and Sky, as well as via IPTV providers such as Verizon FIOS and AT&T U-verse is referred to as a "satellite channel". Alternative terms include "non-broadcast channel" or "programming service", the latter being mainly used in legal contexts. Examples of cable/satellite channels/cable networks available in many countries are HBO, Cinemax, MTV, Cartoon Network, AXN, E!, Fox Life, Discovery Channel, Canal+, Eurosport, Fox Sports, Disney Channel, Nickelodeon, CNN International, ESPN, GMA Pinoy TV and The Filipino Channel.

The abbreviation CATV is often used for cable television. It originally stood for Community Access Television or Community Antenna Television, from cable television's origins in 1948. In areas where over-the-air TV reception was limited by distance from transmitters or mountainous terrain, large "community antennas" were constructed, and cable was run from them to individual homes. The origins of cable broadcasting for radio are even older as radio programming was distributed by cable in some European cities as far back as 1924.

History in North America

Cable television began in the United States as a commercial business in 1950, although there were small-scale systems by hobbyists in the 1940s.

The early systems simply received weak (broadcast) channels, amplified them, and sent them over unshielded wires to the subscribers, limited to a community or to adjacent communities. The receiving antenna would be higher than any individual subscriber could afford, thus bringing in stronger signals; in hilly or mountainous terrain it would be placed at a high elevation.

At the outset, cable systems only served smaller communities without television stations of their own, and which could not easily receive signals from stations in cities because of distance or hilly terrain. In Canada, however, communities with their own signals were fertile cable markets, as viewers wanted to receive American signals. Rarely, as in the college town of Alfred, New York, U.S. cable systems retransmitted Canadian channels.

Although early (VHF) television receivers could receive 12 channels (2-13), the maximum number of channels that could be broadcast in one city was 7: channels 2, 4, either 5 or 6, 7, 9, 11 and 13, as receivers at the time were unable to receive strong (local) signals on adjacent channels without distortion. (There were frequency gaps between 4 and 5, and between 6 and 7, which allowed both to be used in the same city).

As equipment improved, all twelve channels could be utilized, except where a local VHF television station broadcast. Local broadcast channels were not usable for signals deemed to be priority, but technology allowed low-priority signals to be placed on such channels by synchronizing their blanking intervals. Similarly, a local VHF station could not be carried on its broadcast channel as the signals would arrive at the TV set slightly separated in time, causing "ghosting".

The bandwidth of the amplifiers also was limited, meaning frequencies over 250 MHz were difficult to transmit to distant portions of the coaxial network, and UHF channels could not be used at all. To expand beyond 12 channels, non-standard "midband" channels had to be used, located between the FM band and Channel 7, or "superband" beyond Channel 13 up to about 300 MHz; these channels initially were only accessible using separate tuner boxes that sent the chosen channel into the TV set on Channel 2, 3 or 4.

Before being added to the cable box itself, these midband channels were used for early incarnations of pay TV, e.g. The Z Channel(Los Angeles) and HBO but transmitted in the clear i.e. not scrambled as standard TV sets of the period could not pick up the signal nor could the average consumer `de-tune' the normal stations to be able to receive it.

Once tuners that could receive select mid-band and super-band channels began to be incorporated into standard television sets, broadcasters were forced to either install scrambling circuitry or move these signals further out of the range of reception for early cable-ready TVs and VCRs. However, once all 181 allocated cable channels had been incorporated, premium broadcasters were left with no choice but to scramble.

Unfortunately for pay-TV operators, the descrambling circuitry was often published in electronics hobby magazines such as Popular Science and Popular Electronics allowing anybody with anything more than a rudimentary knowledge of broadcast electronics to be able to build their own and receive the programming without cost.

Later, the cable operators began to carry FM radio stations, and encouraged subscribers to connect their FM stereo sets to cable. Before stereo and bilingual TV sound became common, Pay-TV channel sound was added to the FM stereo cable line-ups. About this time, operators expanded beyond the 12-channel dial to use the "midband" and "superband" VHF channels adjacent to the "high band" 7-13 of North American television frequencies. Some operators as in Cornwall, Ontario, used a dual distribution network with Channels 2-13 on each of the two cables.

During the 1980s, United States regulations not unlike public, educational, and government access (PEG) created the beginning of cable-originated live television programming. As cable penetration increased, numerous cable-only TV stations were launched, many with their own news bureaus that could provide more immediate and more localized content than that provided by the nearest network newscast.

Such stations may use similar on-air branding as that used by the nearby broadcast network affiliate, but the fact that these stations do not broadcast over the air and are not regulated by the FCC, their call signs are meaningless. These stations evolved partially into today's over-the-air digital subchannels, where a main broadcast TV station e.g. NBS 37* would – in the case of no local CNB or ABS station being available – rebroadcast the programming from a nearby affiliate but fill in with its own news and other community programming to suit its own locale. Many live local programs with local interests were subsequently created all over the United States in most major television markets in the early 1980s.

This evolved into today's many cable-only broadcasts of diverse programming, including cable-only produced television moviesand miniseries. Cable specialty channels, starting with channels oriented to show movies and large sporting or performance events, diversified further, and "narrowcasting" became common. By the late 1980s, cable-only signals outnumbered broadcast signals on cable systems, some of which by this time had expanded beyond 35 channels. By the mid-1980s in Canada, cable operators were allowed by the regulators to enter into distribution contracts with cable networks on their own.

By the 1990s, tiers became common, with customers able to subscribe to different tiers to obtain different selections of additional channels above the basic selection. By subscribing to additional tiers, customers could get specialty channels, movie channels, and foreign channels. Large cable companies used addressable descramblers to limit access to premium channels for customers not subscribing to higher tiers, however the above magazines often published workarounds for that technology as well.

During the 1990s, the pressure to accommodate the growing array of offerings resulted in digital transmission that made more efficient use of the VHF signal capacity; fibre optics was common to carry signals into areas near the home, where coax could carry higher frequencies over the short remaining distance. Although for a time in the 1980s and 1990s, television receivers and VCRs were equipped to receive the mid-band and super-band channels. Due to the fact that the descrambling circuitry was for a time present in these tuners, depriving the cable operator of much of their revenue, such cable-ready tuners are rarely used now - requiring a return to the set-top boxes used from the 1970s onward.

The conversion to digital broadcasting has put all signals - broadcast and cable - into digital form, rendering analog cable television service mostly obsolete, functional in an ever-dwindling supply of select markets. Analog television sets are still[when?]accommodated, but their tuners are mostly obsolete, oftentimes dependent entirely on the set-top box.

Deployments by continent

Cable television is mostly available in North America, Europe, Australia, South Asia and East Asia, and less so in South America and the Middle East. Cable television has had little success in Africa, as it is not cost-effective to lay cables in sparsely populated areas. So-called "wireless cable" or microwave-based systems are used instead.

Cable television, generally, any system that distributes television signals by means of coaxial or fibre-optic cables. The term also includes systems that distribute signals solely via satellite. Cable-television systems originated in the United States in the late 1940s and were designed to improve reception of commercial network broadcasts in remote and hilly areas. During the 1960s they were introduced in many large metropolitan areas where local television reception is degraded by the reflection of signals from tall buildings. Commonly known as community antenna television (CATV), these cable systems use a “community antenna” to receive broadcast signals (often from communications satellites), which they then retransmit via cables to homes and establishments in the local area subscribing to the service. Subscribers pay a specified monthly service charge in addition to an initial installation fee.

Established in 2000, the Soukacatv.com (DSW) main products are modulators both in digital and analog modulators,amplifier and combiner. We are the leading communication supplier in manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular products all over the world. For more, please access to https://www.soukacatv.com/.

Source: From Wikipedia, the free encyclopedia

What are the differences between analog TV and digital TV? | Soukacatv.com

About the analog TV and digital TV, we found the differences are as follows:

Digital TVs are beginning to gain widespread acceptance all over the world while analog TVs are slowly disappearing. The primary difference between these two types is with the signals that they can process. Analog TVs are restricted to analog signals while Digital TVs can process digital signals and analog signals.

Since analog TVs can only process analog signals, it is also quite prone to the problems that analog signals experience. Problems like noise, interference, and even distorted displays are very common in analog TVs. Though digital TVs can still be affected by these problems if the signal is also analog, switching to a digital signal almost eliminate it.

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Analog TV sets use cathode ray tubes as their display while digital TV sets use flat panel display like LCD, plasma, or LED. Consequently, analog TV sets are big and bulky compared to digital TV sets. Analog TVs also consume a lot more power compared to digital TVs.

Digital TV sets can be in 480p or more commonly known as SD or even in 780p or 1080i/p which is known as HD or high definition. HD makes it possible to increase the size of the TV sets without compromising the quality of the image on screen. Analog TV sets use the standard definition. Though there have been attempts to implement HDTV analog sets at first, the requirements in terms of bandwidth were just too great for it to be feasible.

Analog TVs are usually limited to sizes of below 30 inches because creating much larger screens pose greater challenges without any real gains in the image quality. Digital TVs have been growing since they were made and screen sizes of over 50 inches are now quite common.

There are still some benefits that you can get with analog TVs that are mostly due to its use of CRT. Analog screens have a very fast response time making it excel in showing fast motion videos. Analog TVs also have better contrast compared to most digital TVs. There might still be advantages for analog TVs, but developments in technology have begun to improve on the shortcomings of digital TVs.

Summary:
 1. Analog TVs can only accept analog signals while Digital TVs can accept both digital and analog signals
 2. Analog TVs are prone to noise and distortion while Digital TVs are not
 3. Analog TVs are usually made with CRT displays while Digital TVs use flat panel displays
 4. Digital TVs can be in HD while analog TVs can only be in SD
 5. Analog TVs are restricted to under 30 inches while Digital TVs above 50 inches are already common
 6. Analog TVs have advantages over digital TVs that are largely related to the CRT

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Source: differencebetween

Basic Introduction of Modulation and Demodulation | Digital & Analog Modulators--Soukacatv.com

Radio waves can carry audio, video, and digital information over great distances by using changes in a carrier wave’s amplitude, frequency, or phase to represent the information being transmitted.

Information can be sent from a transmitter to a receiver by means of modulation and demodulation, respectively, whether those signals are light waves moving through optical cables, radio waves through metallic cables, or radio waves propagating through the air. The electromagnetic (EM) waves that transport the information are referred to as carrier signals, while the information they carry may be in the form of audio, video, or data.

By changing the amplitude, frequency, or phase, or a combination of the three signal characteristics, information can be added as modulation to a signal. Due to the increased amount of information for transmission and reception, signal-modulation techniques have advanced in their capabilities to handle more data for a given amount of occupied bandwidth, although they have also grown more complex in the process. Modulation of a radio wave can be performed by varying one or more of its signal components—amplitude, frequency, or phase—while keeping its other signal components constant. (Pulse modulation is yet another form of modulation, without a carrier, in which pulses with precisely known characteristics are transmitted and details can be learned about a target by receiving the reflected pulses from the target.)

AM & FM

The simplest form of carrier modulation, amplitude modulation (AM), has long been the basis for sending audio information to listeners with radios operating at carrier frequencies from about 535 to 1,605 kHz in the commercial broadcast band. AM is also used for maritime communications and navigation, as well as aircraft navigation, at carrier frequencies from 30 to 535 kHz.

In AM radio broadcasts, the amplitudes of the lower and upper sidebands of the center frequency of a broadcast channel are modulated with the audio content from a radio station, to be demodulated at the receiver of a listener. The lower and upper sidebands extend out from the carrier frequency, usually occupying a total bandwidth of about 25% around the carrier frequency. The audio content from a received AM radio wave can be recovered or demodulated by using a diode to rectify the signals and extract the audio content, or else via filtering to separate the high-frequency carrier signal from the audio content.

In frequency modulation (FM), the frequency of the carrier signal is varied as a function of the message or information. As with AM, audio content is the most commonly transmitted information using FM, such as in commercial FM broadcast radios operating on channels from 88 to 108 MHz. FM can be created by applying message signals directly to a voltage-controlled oscillator (VCO), so that the VCO’s output will be a function of the input signal.

Phase-modulation and -demodulation techniques are more complex than modulation and demodulation based on amplitude and frequency. However, they provide the benefit of higher data rates for the amount of bandwidth consumed. Phase modulation is the basis for many digital modulation formats, in which a modulated signal is divided into in-phase (0 deg.) and quadrature (90 deg.) signal components. In contrast to sending video or audio information, digitized information can be easily transmitted by means of digital modulation formats since the modulated information need not be sent continuously in time, but can be sent in bursts or staggered with time and reconstructed at the receiver and demodulator.

Keying in on Digital Modulation

Digital modulation relies on digital signal processing, such as digital-to-analog converters (DACs) at a receiver and analog-to-digital converters (ADCs) at a transmitter to transform analog information (e.g., audio or video) into a digital form that can then be represented by varying the characteristics of a carrier wave. The three fundamental types of digital modulation—amplitude-shift-keying (ASK), frequency-shift-keying (FSK), and phase-shift-keying (PSK) modulation—use changes in amplitude, frequency, and phase to represent digital bits “0” and “1.” 

In ASK, the signal amplitude is varied as a function of the information to be transmitted, and all other parameters of the signal remain constant. When sending digital information, one amplitude represents a 0 digital bit while a higher or lower amplitude represents the 1 bit. Waveforms with ASK have the rapidly changing amplitude levels representing a digital bit stream.

In FSK, two different frequencies are used to represent the digital 0 and 1 values. The shift in frequencies in FSK is implemented in different ways, notably in a noncoherent or coherent format. In noncoherent FSK, discontinuities exist between the frequencies that represent the digital bits. Termed “mark” and “space” frequencies, they are used as kinds of frequency gaps to separate the bit-representing frequencies. In coherent FSK, the changes in bit-representing frequencies are instantaneous, without phase discontinuities between the frequencies.

In PSK, the phase of the carrier is discretely changed to denote the different digital bits. The phase can be changed in relation to a reference phase, such as using 0 deg. for a 0 digital bit and 180 deg. to represent the digital 1 bit, or if a difference of 180 deg. is used to denote different digital bits, one of the bits may be represented by a relative phase of –90 deg. and the other by +90 deg. In such a simple, biphase modulation format, the two phase angles of the carrier represent two digital bits of information, so that the modulation rate is equal to the bit rate. But if a greater number of phase angles is used, the bit rate can be increased in parallel with an increasing number of phase angles.

In a quadrature phase-modulation format such as quadrature phase shift keying (QPSK), where four phase angles are used to represent the digital bits, two bits of digital information are able to be carried with each phase angle, so that the information can be represented as 00, 01, 10, and 11. Similarly, if eight phase angles are employed in the phase-modulation scheme, then three digital bits can be represented by each of eight possible phase angles. In turn, the bit rate will increase as the number of phase angles grows in the phase-modulation scheme.

As a result, many digital-modulation formats based on changes in phase attempt to represent the greatest number of digital bits possible by variations in phase, so as to support the highest bit rates possible. This performance parameter of a modulated waveform, spectral efficiency, refers to the number of bits that can be transmitted during a given period of time and for a given portion of bandwidth, usually measured as b/s/Hz.

ASK can be affected by nonlinearities in a system—for example, any form of nonlinear distortion like nonlinear amplification—so it is essential that components with extremely linear performance be used to preserve the amplitude characteristics of a transmitted and received signal. FSK, on the other hand, requires high frequency stability in a system’s signal sources, such as VCOs used for local oscillators (LOs) in receiver and transmitters. To maintain high frequency stability, oscillators in FSK systems are typically stabilized by means of phase-locked loops (PLLs) to synchronize the frequency and phase of the system’s frequency sources to a common reference source. In addition, PSK depends on tight phase tolerances in a system, such as the lengths of transmission lines, where variations can mean increasing phase errors with increasing transmission frequencies.

Editor’s Note: This is part one of a two-part article on the basics of modulation and demodulation. The next installment will examine some of the more complex forms of digital modulation, and explain the use of the time domain and pulsed signals in systems employing pulse modulation (e.g., military radars and automotive collision-avoidance systems). Part 2 will also review the types of hardware needed for each type of modulation/demodulation format, and which modulator/demodulator performance parameters are most critical to achieving good communications-systems performance with high spectral efficiency.

Established in 2000, the Soukacatv.com (DSW) main products are modulators both in digital and analog modulators, amplifier and combiner. We are the leading communication supplier in

manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular

products all over the world. For more, please access to https://www.soukacatv.com/.

Source: mwrf.com

Digital TV Modulator Market 2018 Competitive Landscape Research Forecast to 2023

Global Digital TV Modulator Market report provide emerging opportunities in the market and the future impact of major drivers and challenges and, support decision makers in making cost-effective business decisions. The Digital TV Modulator market 2018-2023 report assesses key opportunities in the market and outlines the factors that are and will be driving the growth of the Digital TV Modulator industry.

Digital TV Modulator Market report includes the company profile, product specifications, capacity, production value, and market shares for each company. Digital TV Modulator Market contains capacity, production, production value, cost/profit, supply/demand, import/export, Market Forecast, Analysis of Industry Chain Structure, Economic Impact, Market Dynamics, and Proposals for New Project.

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TOC of Digital TV Modulator Market Report Covered:

Chapter 1: Introduction of Digital TV Modulator Industry
1.1 Brief Introduction of Digital TV Modulator
1.2 Development of Digital TV Modulator Industry
1.3 Status of Digital TV Modulator Industry

Chapter 2: Analysis Key Manufacturers in Digital TV Modulator Market
2.1 Company Profile
2.2 Product Information
2.3 2012-2018 Production Information
2.4 Contact Information

Chapter 3: Market Status of Digital TV Modulator Market
3.1 Market Competition of Digital TV Modulator Industry by Company
3.2 Market Competition of Digital TV Modulator Industry by Country (USA, EU, Japan, Chinese etc.)
3.3 Market Analysis of Digital TV Modulator Consumption by Application/Type

Chapter 4: Global and Chinese Economic Impact on Digital TV Modulator Market
4.1 Global and Chinese Macroeconomic Environment Analysis
4.1.1 Global Macroeconomic Analysis
4.1.2 Chinese Macroeconomic Analysis
4.2 Global and Chinese Macroeconomic Environment Development Trend
4.2.1 Global Macroeconomic Outlook
4.2.2 Chinese Macroeconomic Outlook
4.3 Effects to Digital TV Modulator Market

The Digital TV Modulator market 2018-2023 report highlight the economy, past and emerging trend of industry, and availability of basic resources. Furthermore, the Digital TV Modulator market report explains development trend, analysis of upstream raw materials, downstream demand, and current market dynamics is also carried out. In the end, the report makes some important proposals for a new project of Digital TV Modulator market before evaluating its possibility.

Established in 2000, the Soukacatv.com (DSW) main products are modulators both in digital

and analog modulators,amplifier and combiner. We are the leading communication supplier in

manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular

products all over the world. For more, please access to https://www.soukacatv.com/.

Source: https://faircolumnist.com/digital-tv-modulator-market-2018-key-profiles-driver-outlook-competitive-landscape-research-forecast-to-2023/

RF Modulators Market Growth Prospects, Key Vendors, And Future Scenario & Outlook To 2023 | Soukacatv.com

HTF MI released a new market study on Global RF Modulators Market with 100+ market data Tables, Pie Chat, Graphs & Figures spread through Pages and easy to understand detailed analysis. At present, the market is developing its presence. The Research report presents a complete assessment of the Market and contains a future trend, current growth factors, attentive opinions, facts, and industry validated market data. The research study provides estimates for Global RF Modulators Forecast till 2025.

Important Features that are under offering & key highlights of the report :

1) What all companies are currently profiled in the report?Following are list of players that are currently profiled in the the report “Synergy Microwave Corporation, Advanced Microwave Inc, Analog Devices, Crane Aerospace & Electronics, G.T. Microwave, Inc, Integrated Device Technology, L3 Narda-MITEQ, Linear Technology, MACOM, Mini Circuits, Planar Monolithics Industries, Polyphase Microwave, Qorvo, SAGE Millimeter, SignalCore, Sirius Microwave, Skyworks, Teledyne Cougar & Teledyne RF & Microwave”

** List of companies mentioned may vary in the final report subject to Name Change / Merger etc.

2) Can we add or profiled new company as per our need?Yes, we can add or profile new company as per client need in the report. Final confirmation to be provided by research team depending upon the difficulty of survey.** Data availability will be confirmed by research in case of privately held company. Up to 3 players can be added at no added cost.
3) What all regional segmentation covered? Can specific country of interest be added?Currently, research report gives special attention and focus on following regions:North America, United States, Canada, Mexico, Asia-Pacific, China, India, Japan, South Korea, Australia, Indonesia, Singapore, Rest of Asia-Pacific, Europe, Germany, France, UK, Italy, Spain, Russia, Rest of Europe, Central & South America, Brazil, Argentina, Rest of South America, Middle East & Africa, Saudi Arabia, Turkey & Rest of Middle East & Africa** One country of specific interest can be included at no added cost. For inclusion for more regional segment quote may vary.

4) Can inclusion of additional Segmentation / Market breakdown is possible?
Yes, inclusion of additional segmentation / Market breakdown is possible subject to data availability and difficulty of survey. However a detailed requirement needs to be shared with our research before giving final confirmation to client.
** Depending upon the requirement the deliverable time and quote will vary.

The in-depth information by segments of the Global RF Modulators market helps monitor future profitability & to make critical decisions for growth. The information on trends and developments focuses on markets and materials, capacities, technologies, CAPEX cycle and the changing structure of the Global RF Modulators Market.

Established in 2000, the Soukacatv.com (DSW) main products are modulators both in digital and analog modulators, amplifier and combiner. We are the leading communication supplier in manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular products all over the world. For more, please access to https://www.soukacatv.com/.

Source: thehonestanalytics