Is the Television

A television camera initiates the process by capturing the visual and auditory elements of a TV program. This captured content is then converted into electrical signals. A television set receives these signals and decodes them back into the images and sounds we see and hear.

The TV Signal

A conventional television camera transforms images into an electrical signal known as the video signal. This video signal carries the visual information in the form of minute dots called pixels. Simultaneously, the camera’s microphone captures the sound and converts it into a separate electrical signal, the audio signal. The combination of these two signals, video and audio, constitutes the complete TV signal.

Digital television (DTV) represents a more recent approach to handling television signals. In DTV, pictures and sound are encoded as numerical data, similar to the way computers process information. This digital format allows for the transmission of more information compared to traditional analog signals, resulting in superior picture and sound quality. High-definition television (HDTV) is a specific type of DTV that offers exceptionally high resolution and clarity.

A TV signal can be transmitted to a television set through various methods. Local television stations utilize antennas to broadcast signals wirelessly as radio waves. Cable television providers transmit signals through underground cables. Satellites orbiting high above the Earth can also relay signals to specialized antennas known as satellite dishes. Alternatively, a signal can originate from devices directly connected to the television, such as VCRs, DVD players, or DVRs (digital video recorders). These devices can record incoming TV signals for later playback.

Display

A traditional television set functions by converting the video signal into beams of electrons. These electron beams are then projected onto the back of the screen through a picture tube. The beams systematically “paint” the pixels on the screen row by row, creating the visible image. Concurrently, the audio signal is sent to loudspeakers, which reproduce the accompanying sound.

LCD and plasma televisions employ different mechanisms for image formation. They dispense with the picture tube and electron beams, resulting in significantly thinner and lighter televisions that can even be mounted on a wall.

LCD, which stands for liquid crystal display, utilizes a unique substance that exhibits properties of both liquids and solids. The display transmits light and electric current through this liquid crystal material. The electric current causes the solid particles within the liquid crystal to rearrange themselves, selectively blocking or allowing light to pass through, thereby forming the picture on the screen.

A plasma display, on the other hand, consists of numerous tiny colored lights containing a gas called plasma. When an electric current passes through the plasma, it emits light, which in turn creates the picture. Each tiny light acts as a pixel, contributing to the overall image.