Analog TV worked by broadcasting radio waves containing both picture and sound information from a television station's transmission tower.
Here's a more detailed breakdown:
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Signal Encoding: The TV camera converted visual images into an electrical signal. This signal's strength varied depending on the brightness of the image at each point. Sound was similarly converted into an audio signal. These signals were then combined and modulated onto a radio wave carrier.
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Transmission: The television station used a powerful transmitter and a large antenna (transmission tower) to broadcast these modulated radio waves across a geographical area. Different channels corresponded to different radio frequencies.
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Reception: A home television antenna picked up these radio waves. The TV set's tuner selected the desired channel (frequency).
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Decoding: Inside the TV, the radio wave signal was demodulated, separating the audio and video information.
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Image Display: The video signal controlled an electron beam that scanned across the inside of the TV screen (a cathode ray tube or CRT). The intensity of the beam varied according to the video signal, causing phosphors on the screen to glow with varying brightness, thus creating the picture.
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Sound Reproduction: The audio signal was amplified and sent to a speaker, producing the sound.
Key Components in Analog TV Transmission and Reception:
| Component | Function |
|---|---|
| Transmission Tower | Broadcasts the radio wave signal containing picture and sound information. |
| TV Antenna | Receives the radio wave signal. |
| Tuner | Selects the desired channel (frequency). |
| Demodulator | Separates the audio and video information from the radio wave. |
| Cathode Ray Tube | Displays the picture. |
| Speaker | Reproduces the sound. |
Essentially, analog TV worked by converting visual and audio information into radio waves, transmitting those waves through the air, and then receiving and decoding those waves back into a picture and sound on a television set.
