Going From Analog to Digital Television
Television first became commercially available in the 1930s. From those early days up until recently, analog television was by far the standard. But, what is analog television? And what about this digital television transition? These topics will be explored.
Analog Television
Analog Television – or Analogue Television – is comprised of the NTSC, PAL, and SECAM standards. These are known as analog encoding standards. Regardless of which encoding standard is used (with NTSC – the National Television Systems Committee – being used primarily in the US), the process of broadcasting analog television is the same. Broadcasters encode the signal using one of the standards, then modulate this signal onto a VHF or UHF carrier. On the other end, a television antenna receives the analog broadcast, then essentially draws the picture on the screen, one frame at a time.
The televisions trick the human eye into sensing motion by rapidly drawing sequences of images on the screen. The single images are drawn at such a fast pace that motion is perceived. The rate at which these images are drawn
is called the frame rate. Standard color analog television is broadcast at 29.97 Hz in the US.
While that standard has served well for over 90 years, it about to be permanently retired in favor of digital television. The transition from analog to digital television has begun.
Simulcast: Helping to Ease the Transition
What most broadcast companies are doing now is broadcasting their signal in both analog and digital. This provides “early adopters” the ability to enjoy digital television now, and gives those who have not either purchase a digital converter box or a new television time to adjust.
However, simulcasting will not last forever; eventually, only digital broadcasts will be available.
Digital Broadcasts
Digital broadcasts use a single digital transmission system. The digital broadcast standard in the US is ATSC (Advanced Television Systems Committee ). These digital television are based on the MPEG-2 multiplexed data stream standard, and use the familiar MPEG-2 video codec. ATSC uses a proprietary Zenith-developed modulation called “8-VSB“.
So why the transition to Digital Television? The most common cited reasons are 1) improved quality of digital broadcasts over analog – including picture and sound, 2) additional channel (multicasting), 3) valuable radio spectrum space will be made available for other services, which brings one to the final point of 4) bringing in large amounts of money at auctions for control of the newly available wireless spectrum.
Digital Converter Boxes
If you have an analog television and rely on free, over-the-air television, you’re going to need a digital converter box. The digital converter box will take the new digital television broadcast and converter it to an analog signal that your television can display. Without a digital converter box, your television will become useless for watching over-the-air broadcasts after the mandatory digital television switchover on 2/17/2009.
Interested in learning more about digital converter boxes and which digital converter box is right for you? Read more at Digital Converter Boxes.
Digital television is coming; analog television is leaving.
Are you ready?
Analog to Digital Television 