Analog Broadcasts
Television has been broadcast in analog since its inception in the 1940’s. Analog broadcasts use radio frequency waves (AM and FM) on the broadcast spectrum to transmit pictures and sound separately. Analog television displays pictures on a 4x3 aspect ratio (screen width to height) and uses FM stereo sound.
Although analog television has been the standard for over 50 years, the service is low quality and less efficient by today’s standards. The picture can be unstable and “snowy,” especially when received over-the-air with an antenna.
When broadcasting in analog, television networks can only transmit one channel of programming using the allotted spectrum. There is no room on the spectrum to offer advanced services such as additional programming and interactive viewing options.
Analog, digital, and HDTV’s can pick up an analog signal; however, digital and HDTV’s won’t display the programming in true digital quality with analog service.
Digital Broadcasts
For the last 10 years, television stations have been preparing to send signals digitally. Digital broadcasts use radio frequency to transmit computer code (ones and zeros) and display it as pictures and sound simultaneously. Digital television can display a picture on a 16x9 aspect ratio (screen width to height) and uses multi-channel digital surround sound for a movie-like experience at home.
Digital television displays pictures in higher resolution than analog, allowing for a crisp, clear, more detailed picture and zero interference.
A digital signal is compressed, so it is also more efficient to broadcast on the spectrum. The freed up space allows for advanced features including more channels, program guide data, and interactive features.
Only digital and HDTV’s can pick up a digital signal and display it in true digital quality. Analog televisions need a subscription to cable or satellite service or a digital converter box in order to pick up a digital signal.
