How Television broadcast works

Summary

This video explains how a television broadcast works, starting with a camera capturing light from a scene. The light is split into the primary colors—red, green, and blue—by a prism system, which then creates electrical charges on a CCD. These charges are converted into video signals and combined for transmission. The TV signal is broadcast via antenna, picked up by a receiver, and separated into audio and video. The video signal is decoded into red, green, and blue components, which are used to light up phosphors on the screen, recreating the image for viewers to see.

Takeaways

• 😀 Television broadcasts begin with a camera that captures light from a scene.
• 😀 Most cameras use a prism system to break light into three primary colors: red, green, and blue.
• 😀 The camera's image sensors, called CCDs, create electric charges when exposed to light.
• 😀 The CCDs release electric charges line by line, generating a video signal.
• 😀 The video signal is encoded and combined with audio into a single signal for transmission.
• 😀 The transmitter broadcasts the combined signal as an electromagnetic wave within a frequency range or channel.
• 😀 A TV antenna picks up broadcast signals, converting them into electric current.
• 😀 The TV tuner selects the desired broadcast signal, which is separated into audio and video components.
• 😀 The video signal is divided into three signals: red, green, and blue.
• 😀 The TV screen is coated with phosphors that glow in red, green, and blue when hit by electron beams.
• 😀 The electron guns in the TV shoot beams line by line, controlling the brightness of the phosphors to recreate the image.

Q & A

How does a television camera break light from a scene?

A television camera uses a prism system to break light from a scene into the three primary colors: red, green, and blue.

What is the role of a Charged Coupled Device (CCD) in a television camera?

The CCD is an image sensor that captures the light falling on it and converts the light into a pattern of electric charges.

What happens when light falls on a CCD in a television camera?

When light falls on the CCD, it produces a pattern of electric charges, which are then released line by line to create a video signal.

How are the separate video signals processed in a television broadcast?

The separate video signals are combined by an encoder into a single signal, which is then transmitted along with audio to a transmitter.

What does a television transmitter do with the audio and video signals?

The transmitter produces a television signal by combining the audio and video signals and broadcasts it as an electromagnetic wave on an assigned frequency or channel.

How does a television antenna work?

A television antenna picks up all broadcast signals within its range, which produce an electric current inside the antenna.

What happens when the signal reaches a television receiver?

Inside the receiver, the tuner selects the desired broadcast signal, and other components separate the audio and video signals.

How is the video signal processed inside a television?

The video signal is divided into three separate signals: one for red, one for green, and one for blue.

What is the role of phosphors on a TV screen?

The screen is coated with phosphors, which are materials that glow when struck by an electron beam, reproducing the image recorded by the camera.

How is the brightness of the phosphors controlled on a television screen?

The strength of the electron beam, controlled by the video signal, determines how brightly the phosphors glow, creating the image on the screen.