The switch to digital TV promises several benefits:

Viewers should notice improvements in picture and sound quality, particularly in the case of high-definition (HDTV) broadcasts. (To get the full effect, you’ll need a high-definition set, and the broadcaster and, if applicable, cable or satellite provider must provide a high-definition signal.)...

Standard Definition TV (SDTV)

SDTV is the basic level of quality display and resolution for both analog and digital. Transmission of SDTV may be in either the traditional (4:3) or widescreen (16:9) format. Digital SDTV provides pictures and sound comparable to the best available analog TV....

The difference between Analog TV and Digital TV boils down to the way the TV signal is transmitted. Standard analog TV is transmitted in a manner similar to radio.

In fact, the video signal of analog television is transmitted in AM, while the audio is transmitted in FM. Analog TV is subject to interference, such as ghosting and snow, depending on the distance and geographical location of the TV receiving the signal....

“DTV” is a general reference to Digital Television, as compared to “analog” Television. DTV broadcasts can be either HDTV (high-definition television) or SDTV (standard-definition television). HDTV can broadcast at resolutions typically as high as 1920 by 1080 pixels (2 million pixels), whereas the resolutions of SDTV broadcasts are typically only as high as 640 by 480 pixels (290,000 pixels).

In comparison, analog television produces a total of about 210,000 pixels. Broadcasters and cable providers can choose which format of DTV they transmit, and most DTV's and new HDTV set-top boxes will be able to receive the signal regardless of which format is transmitted. Note, however, that your standard analog TV set will not be able to receive DTV signals (neither HDTVnor SDTV). ...

If you receive only free over-the-air television programming, the type of TV you own, either a digital TV or an analog TV, is very important. Consumers who receive only free over-the-air television may view digital programming through a TV set with a built-in digital tuner (integrated DTV) or a digital-ready monitor with a separate digital tuner set-top box. (Both of these digital television types are referred to as a DTV). The only additional equipment required to view over-the-air digital programming with a DTV is a regular antenna, either on your roof or a smaller version on your TV such as “rabbit ears.”

If you have an analog television, you will have to purchase a digital-to-analog set-top converter box to attach to your TV set to be able to view over-the-air digital programming....

TVs connected to cable, satellite, or other pay services do not require a TV converter box from this program to receive programs after February 17, 2009. Check with your cable or satellite provider to determine how they will support your analog set after February 17, 2009. Time Warner, Comcast and Direct TV Cable are already broadcasting digital programming.

The cable companies have agreed to continue to furnish analog versions of the locally available over the air digital TV until 2012, or to furnish converter boxes. What they choose to do regarding any other analog TV they presently have, is up to them....

Digital TVs have labels as “Integrated Digital Tuner,” “Digital Tuner Built-In,” “Digital Receiver,” or “Digital Tuner,” “DTV,” “ATSC,” or “HDTV” (High Definition television). If your television equipment contains any of these labels or markings and it contains a digital tuner, you can view over-the-air digital programming without the need for a digital-to-analog converter box.

The only televisions that have DTV turners are those that since about 1998, have been sold as having an integrated or “built-in” DTV or HDTV broadcast turner. (An HD set sold as a “monitor” or “HD-ready” is capable of displaying HDTV but does not have a built-in HDTV turner) Most TVs with analog turners are now required by the FCC to also be marketed with built-in or separate DTV or HDTV turners – this will soon be a requirement for all TVs....

There are many quality levels of digital television programming. The most common are:

Standard Definition TV (SDTV) - SDTV is the basic level of quality display and resolution for both analog and digital. Transmission of SDTV may be in either the traditional (4:3) or widescreen (16:9) format....

A Digital to Analog Converter Box or Digital Television (DTV) Converter Box is an electronic device that converts the new free over-the-air digital signal into an analog signal viewable on older “analog” television set. A digital to analog converter box will not give you a digital picture on an analog TV set, but will not convert your analog TV set into a high definition TV, also known as a HDTV.

A TV converter box is a stand-alone device that allows your antenna to receive and convert digital signals into a format analog television sets can display. A DTV converter box hooks up to your analog television set and over-the-air antenna. The box converts the digital television signal into an analog format, making it viewable on your analog TV set. Several of these devices have already been shown and, while few were initially available, they are becoming more available by the day.
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Multicasting is the ability to transmit a single stream to multiple subscribers at the same time. Unlike conventional streaming, it does not need one stream per recipient. Instead, there is one stream on any one segment of the network on which there is a subscriber.

Using the same amount of spectrum required for one analog program, multicasting allows broadcast stations to offer several channels of digital programming at the same time. For example, a local TV station elects to send out three DTV programs. The first program offers HDTV shows and sports, while the second offers SD versions of the same programming. Finally, a third program carries continuous local weather information. Your digital TV set-top receiver or integrated TV will automatically find all of these programs for you and identify each with a unique channel number....