Digital Television (DTV) is the transmission of television signals using digital rather than conventional analog methods. Analog transmission is in the form of a constantly variable wave; digital transmission consists of an electrical pulse which has two possibilities: on and off (or positive and negative), which are represented by a one and a zero. Because a digital signal does not fluctuate, but is either perfectly intact or totally absent, a digital transmission is more precise than an analog transmission.

Advantages of DTV over analog TV include:-
  • Superior image resolution (detail) for a given bandwidth
  • Smaller bandwidth for a given image resolution
  • Compatibility with computers and the Internet
  • Interactivity
  • Superior audio quality
  • Consistency of reception over varying distances
There are the two categories of display formats for Digital Television (DTV) transmissions; one is Standard definition television (SDTV) and another High definition television (HDTV) which is becoming the standard. HDTV provides a higher quality display with a vertical resolution display from 720p to 1080i. The p stands for progressive scanning, which means that each scan includes every line for a complete picture, and the i stands for interlaced scanning which means that each scan includes alternate lines for half a picture.

IN INDIA, as per new Cable TV act the analog television broadcasts on Cable will stop on 31st December 2014. Analog television sets will require Digital Set-Top-Box (STB) to convert Digital Transmissions. In the cities like Delhi, Mumbai, Kolkata & Chennai, Most of the Cable subscribers already have Digital Set-Top-Box (STB). However, people who previously used antennas for "over the air" transmission and Cable Subscribers who now plug the Cable directly into their TV sets will need Digital Set-Top-Box (STB).