televisiosignaali

A televisiosignaali, or television signal, is a carrier wave that transmits audio and video information from a source to a television receiver. Historically, these signals were broadcast over the air using analog radio waves. The analog signal encoded the visual information as varying amplitudes and frequencies of electromagnetic waves, while the audio was typically transmitted on a separate frequency. This analog transmission method was susceptible to interference, leading to picture and sound degradation.

In many parts of the world, analog broadcasting has been replaced by digital television (DTV) transmission. Digital television signals are transmitted as binary data, essentially ones and zeros. This digital format allows for more efficient use of bandwidth and significantly improves signal quality, reducing interference and enabling higher resolutions like high-definition television (HDTV). Digital signals can also carry additional data, such as electronic program guides and multiple audio channels.

The transmission of televisiosignaalit can occur through various methods. Over-the-air (OTA) broadcasting uses radio antennas. Cable television delivers signals through coaxial or fiber optic cables. Satellite television transmits signals from a satellite orbiting Earth to a dish antenna at the viewer's location. Streaming services deliver television content over the internet, with the signal packaged as digital data packets. Regardless of the transmission method, the ultimate goal is to decode the signal at the receiver and present it as a coherent audio-visual experience on the television screen.