What is Digital TV?
Digital TV is a new system using information transmitted as "data bits" – like a computer – to display movie-quality pictures and sound. It replaces the traditional TV system using magnetic waves to transmit and display TV pictures and sound. The difference between analog and digital broadcasting is similar to that between compact discs and cassette tapes.
Are DTV and HDTV the same thing?
No. HDTV, or high-definition television, is the highest quality digital television (DTV) available, offering more than five times the sharpness of today's analog television, along with digital surround sound capability. DTV is also available as EDTV (enhanced definition TV) or SDTV (standard definition TV), each with improved pictures and sound over today's analog televisions.
What is analog television?
Analog television service is the traditional method of transmitting TV signals and has been the standard broadcast technology since the inception of television. Analog television service isn't as efficient as digital television.
Why is America Switching to Digital Television (DTV)?
Digital is a more efficient way to broadcast, and it will free up the airwaves for other services, including public safety services. DTV also provides clearer pictures, more channels, and even free over-the-air high-definition television (HDTV) for consumers with HD television sets.
What is the Digital TV Transition?
The digital TV (DTV) transition is the switch from traditional "analog" TV to "digital" TV, a modern technology with many benefits. On June 12, 2009, traditional analog TV service was shut off. The DTV service turned on. Analog television sets receiving free, over-the-air programming will still work after June 12, 2009, but owners of these TVs will need to use converter boxes to change digital broadcasts back into the old analog format.
When is the Digital TV Transition occurring?
The final transition will be completed on June 12, 2009. At that point, broadcasting of the current "analog" channels will end and the spectrum that had been used for analog transmission will be put to other uses. Until the transition to DTV is complete, television stations will continue broadcasting on both their digital and analog channels.
How do I prepare for the Digital Transition?
Preparing for the DTV transition requires taking 1 of 3 steps by June 12, 2009:
1. Purchase a converter box for each television set in your home that receives TV signals through an antenna.
If you'd like to learn more about converter boxes, download this PDF Fact Sheet or call the toll-free number the National Telecommunications and Information Administration has set: 1-888-DTV-2009.
2. Purchase a new television set with a built-in digital tuner; or
3. Subscribe to cable or satellite that carries the channels you want to watch.
How do I get a set-top converter box for my analog television?
Set-top converter boxes are available for purchase at electronics retailers. The cost of the box is expected to range from $40-70. Consumers who wish to retain their analog television sets may also switch to a cable, satellite or telecommunications service provider.
Do I need to purchase a new television set?
No. Your current television will work as it does now until analog broadcasting stops. Even after the transition is over, your current TV will not become obsolete. A set-top converter box can be used to receive broadcast DTV signals and change them into the format of your current television. In addition, if you use your analog set with a pay service like cable or satellite, it should continue to work as it always has.
Do I need to subscribe to cable or satellite?
No. Digital TV is an over-the-air broadcast system that does not require special wiring to the home. You will need either a converter box or a television with an integrated digital receiver.
Will I need a special antenna to receive DTV over-the-air?
In general, dependable reception of DTV will require the same type of signal reception equipment that currently works to provide good quality reception of analog TV signals. If you now need a roof-top antenna to receive television, the same antenna generally will be needed to receive DTV. You should not have to purchase new antennas that are marketed as "digital ready" or "HD ready." Find helpful and specific information on using an antenna to receive local television broadcast channels in the digital transition world here.
Cable and satellite operators offer a digital package. Is this the same as HDTV?
No. "Digital" and high definition programming are not the same. If you want to watch HDTV programming on cable or satellite, you will need to subscribe to your provider's HDTV package and view the programming on an HDTV set. You may also need a set-top box or new satellite dish to view HDTV programming. Check with your cable or satellite provider to find out what kind of programming you can receive, and what equipment you'll need.
Will I be able to use my VCR, DVD player, camcorder, and gaming console with a digital television set?
Yes. Digital television sets are "backward compatible," meaning existing analog equipment (VCRs, DVD players, camcorders, video games, etc.) will work on digital TV sets, but not in high definition. Their video will be displayed in the maximum resolution that is available with each product.
What are the benefits of digital television?
Digital technology allows the transmission of pictures with higher resolution for dramatically better picture and sound quality. DTV also allows the transmission of several TV programs at once – called "multicasting." DTV technology can also be used to provide interactive video and data services that are not possible with "analog" technology. DTV also frees up scarce and valuable spectrum for public safety and new wireless services. This is possible because the modern technology of DTV is more efficient than analog TV technology, allowing for many new and critical uses of this very limited resource.
Do I already have DTV via digital cable or satellite?
You may have DTV if you subscribe to the digital package and get digital programming. But, digital cable and satellite service aren't necessarily "DTV." Your cable or satellite system may be using digital technology as a more efficient way of delivering programming to your analog TV set. If you have an analog television set, then you aren't viewing true DTV, even though the signal you're watching may be somewhat improved. In order to view true DTV and enjoy all the attributes of digital television service, you must view television signals on a new DTV set.
Similarly, in order to view programs in high-definition (HDTV), you must be equipped with a TV set capable of displaying pictures in high-definition. Your cable or satellite set-top box or the CableCARD from your cable company must provide HDTV channels. Otherwise, you must have an antenna that can receive digital HDTV signals over the air. Check with your cable or satellite provider if you have questions about your service.
What do DTV sets look like?
Most DTV sets have wider, more rectangular screens than current analog TVs. This widescreen format allows for images that are more like those shown in a movie theater. Like current TV sets, a range of sizes is available. As with most new consumer electronics technologies, DTV sets have become less expensive since their introduction.
What is the difference between integrated DTVs and DTV monitors?
An Integrated DTV set is a digital television with a built-in DTV receiver. If you have an Integrated DTV and live in an area served by a DTV broadcast station, you won't need any additional equipment, with the exception of an antenna to receive over-the-air DTV broadcast programming. Integrated TVs can usually receive and display current analog signals.
In contrast, a DTV-Ready monitor isn't capable of receiving over-the-air DTV broadcast programming without additional equipment. A DTV set-top decoder must be connected between the antenna and the monitor to receive and display over-the-air DTV programming.
Confirm with your retailer that the DTV receiver or set-top decoder is compatible with the DTV monitor that you're purchasing. Most monitors have a built in analog receiver and can display regular analog TV programming. They can also display standard resolution video from DVD players and VCRs.
How does digital TV use closed captions?
Analog TV has one format for closed captions in which the captions are encoded invisibly in the analog TV signal. Digital TV can support two formats. The second format is newer and offers more choices of font, color, and size, which can result in better visibility and ease of use. Digital TV carries captions of either format as data along with the digital audio and video content, but unlike analog TV, the captions are not embedded in the video signal. It is up to the originator of the programming to provide the captions for any given program and to select the format. When the captions are decoded and displayed, the resulting text and symbols appear on the screen. The caption decoding function, by U.S. government mandate, is included in all digital TVs that have a screen size 13 inches or larger. It is also included in all separate, stand-alone digital TV tuners (e.g., set top boxes or "STBs"). In either case, the digital TV tuner reads the closed caption data, interprets it, and writes it into the video so it becomes visible when the video is displayed on a screen. (More specifically, the captions are written on top of the video images.)
Can I watch DTV on my home computer?
You can purchase a high definition TV tuner card that adapts your home computer for Digital TV reception. Manufacturers are developing a new generation of computers that will also work as Digital TV receivers.
Can I record HD and other digital programs?
Yes. Set top boxes capable of recording HD programs are currently available from several manufacturers and most cable television providers.
Will I be able to continue to use my existing VCR with a DTV converter box for timed recordings?
Yes, but after the digital transition, you won't be able to pick up over-the-air programs for recording from the tuner in the VCR, so the input to the VCR must be connected to the output of the DTV converter box. The tuner in the DTV converter box will need to be set to the desired channel to be recorded prior to the start of each recording period programmed into the VCR.
Does WTTW transmit a digital signal and have multicast channels?
Yes. With the help of our members, supporters and a capital campaign, WTTW has been preparing for this digital transition for years. Here's a timeline of our own transition:
In April 2002, WTTW began transmitting a digital signal of both our analog broadcast and, at that time, a schedule of high-definition programming straight from PBS.
In September 2003, WTTW opened a new Master Control Center at the station called the Digital Broadcast Operations Center. At that time, WTTW became a fully-digital broadcasting operation - for both our standard definition broadcast and our high definition broadcast. At this time, our digital broadcast paralleled the content in our analog broadcast.
On January 1, 2004, WTTW launched "WTTWD' or "WTTW Digital' (over-the-air channel 11-1; Comcast channel 191) which was the first customized, localized and unique stream of digital programming in Chicago. In other words, the program schedule was not parallel to our analog program schedule and was not fed from PBS. The schedule was put together here at the WTTW Studios by our Broadcasting and Programming teams.
In January of 2006, we launched WTTW Create (over-the-air channel 11-3; Comcast channel 242) which is a schedule of public broadcasting how-to and do-it-yourself programming.
On March 5, 2007, we launched WTTW V-me (over-the-air channel 11-4; Comcast channel 241), the very first Spanish-language public broadcasting television service in Chicago.
With all of these broadcast services, WTTW is committed to and excited about the emergence of new media technologies and digital broadcasting. As always, we are at work preparing for the future with an increased focus on distributing content on multiple platforms with a local sensibility.
How can I watch WTTWDigital?
You can locate WTTWDigital or WTTWD over the air on 11-1. Cable or satellite customers can locate WTTWD on the onscreen menu. Digital sets only. For schedule and more info, visit wttw.com/digital.
How can I watch WTTW Create?
You can locate WTTW Create over the air on 11-3 or on Comcast Digital channel 242. For schedule and more info, visit wttw.com/create.
How can I watch WTTW V-me?
You can locate WTTW V-me over the air on 11-4 or on Comcast Digital channel 241. For schedule and more info, visit wttw.com/vme.
Can I watch WTTW On-Demand?
Yes. If you are a Comcast Cable customer and have access to their On-Demand folders, you will find WTTW on Demand in the "Get Local" folder.
In what resolution does WTTW broadcast?
WTTW broadcasts the "WTTWD" (11-1) HDTV signal in the 720p (progressive scan) format which provides 720 lines and 1280 samples per line resolution. Our standard definition digital program channels (11-2 and 11-3) are broadcast using the 480i (interlaced) standard which provides 480 lines, and 640 samples per line.
Can you explain the difference between 720p and 1080i?
This can be a very detailed and complex explanation; we'll try to keep it simple. Traditional analog television utilizes around 480 horizontal lines of picture information. This system uses an interlaced pattern of line presentation. Starting at the top of the picture and scanning from left to right, going back to the left and proceeding downward by one line the TV scans one half of the 480 lines (240) from top to bottom and then starts again scanning lines in between the ones previously scanned. They are "interlaced" between each other. The picture tube of the TV set uses special phosphors that illuminate and maintain their illumination long enough until the next line gets scanned. 1080i is one of the high definition standards and by using more than twice as many scan lines and more samples per line, we get a much higher resolution than analog TV. It's an interlaced system so it scans 540 lines and goes back to the top and scans 540 more, interlaced between the first. 720p means 720 lines scanned progressively. The scan starts at the top, scans the 720 lines from top to bottom and then starts over again. Both 720p and 1080i are high definition formats and most people cannot tell the difference between the two. WTTW uses the 720p format because it provides excellent quality and allows for us to provide more standard definition channels in our DTV broadcast.
How do I get WTTW transmission if I don't subscribe to cable or satellite, but have a digital TV?
Before the days of cable and satellite TV, the only way to receive a signal from a TV station was with an old fashioned TV antenna. WTTW broadcasts its DTV Channel just as with the analog Channel 11. In both cases, you can receive WTTW and WTTW-DT via an antenna. FYI, WTTW-DT broadcasts on channel 47 in the UHF band so, when choosing an antenna and distribution equipment for your home, be sure to get equipment that works in the UHF band. No need to worry; many stores sell this equipment.
What is the difference between a digital TV and an HD TV?
The Digital Television (DTV) broadcast system allows for stations to choose various program channel formats. These may be "standard definition" (SDTV) channels which have approximately the same resolution as traditional analog television, or "high definition" channels (HDTV) that provide far greater resolution than analog television broadcasts. The DTV broadcast system allows television stations to broadcast an HDTV channel, multiple SDTV channels, or a combination of one HDTV channel and multiple SDTV channels.
Can I get WTTW Create and WTTW V-me if I don't have cable or do I need a digital TV?
You would need to receive WTTW-DT using an antenna and receive it on a digital TV.
For tuning in to WTTWD, WTTW Create or WTTW V-me through the over the air broadcast, how do I set it up for 11-1, 11-2, 11-3 or 11-4?
All digital TVs have a "channel scan" mode on their menus. Hook up the antenna to your DTV system and run the channel scan, and you should find WTTW-DT channels 11-1, 11-2, 11-3 and 11-4. Occasionally we'll hear from viewers who follow this procedure and aren't able to receive WTTW-DT. It is usually recommended that they readjust their antenna and try the scanning process again. Sometimes having the antenna pointed directly at our transmission antenna at Sears Tower doesn't work perfectly. By simply turning the antenna a few degrees either way usually fixes the problem. Of course you need to be within approximately 50 miles of Sears Tower for this to work.
When I watch programs on WTTWD, the sound is not synchronized with the picture.
WTTW Engineering makes a concerted effort to make sure audio and video is synchronized. However, there are times when we receive programming that is not synchronized and often don't have time to fix it. Usually these problems are at the receive end and we instruct viewers to shut off their systems and allow them to restart. This fixes a myriad of problems.
Every time I tune to WTTWD, my receiver crashes and reboots. Why?
One of the opportunities for WTTW is to include data broadcasts with our signal. Early in our attempts at this work, we had defective equipment that caused certain models of DTV receivers to fail. We've removed this equipment and are providing a very robust digital broadcast signal. We haven't had this issue for some time.
Why are descriptions appearing on the screen?
All TV stations have the option of transmitting descriptions of programs they offer on their DTV transmissions. This information is called the "Program Guide" and WTTW uses this to provide viewers some of this information. It will have the name of program, a short description, and other information.
Have other questions that aren't answered here? Let us know.