analog TV

"With an analog television, the signal the television receives is sent as a continuously varying analog waveform. The waveform?s value determines the amount of voltage that will be applied to the electron guns in the back of the picture tube. This directly affects the luminance and chrominance of the picture. In analog television systems, the voltage applied to the electron guns is proportional to the constantly changing video signal voltage. Analog televisions have the following limitations: Analog television channels are susceptible to interference caused by physical features?such as hills and buildings. This interference often takes the form of ghosting on the picture screen. The normal television channel occupies a bandwidth of 6 MHz. With analog televisions, the viewer can see only a limited total number of 6 MHz channels, obviously limiting the total number of possible channels the consumer can receive and view without outside electronic help, that is. In addition, many of the frequency bands that could be used by television channels have to be kept empty because analog television channels spaced too close together can interfere with one another. Although luminance and chrominance signals are separated, the signals can interfere with one another, especially in regions with low signal strength. This can lead to problems with the color display. To watch digital television on an analog television, you need a digital television tuner?in the form of a set-top box/receiver?and some form of antenna or cable connection. See also luminance signal, chrominance signal, ghost, and bandwidth."