Modern Television Technology: Systems, Controls, and Displays

Television Control Systems & Components

Core Functions of TV Control Systems

• Q: What are the specific functions of a television's control system?
• A: The control system is designed to obey user commands, offer practical solutions to problems, and optimize color display.
• Q: Is there a function that allows TV surveillance?
• A: This refers to the suspension aspect of operation.
• Q: How were televisions presented in past years?
• A: They featured digital compatibility.
• Q: What was the manufacturer's purpose in introducing a TV receiving phase?
• A: To facilitate television reception for the user.

SYSCOM and Microcontroller Operations

• Q: What are three functions of the SYSCOM?
• A: SYSCOM functions include increasing operational speed, ensuring accuracy, and preventing errors.
• Q: What is the main circuit involved in the microcontroller?
• A: It primarily handles audio input/output.
• Q: Which devices does the microcontroller rely upon?
• A: It relies on RAM and input/output ports.

User Interaction and Remote Control

• Q: How is contact maintained between the TV and the user?
• A: Through the keyboard.
• Q: What are the three types of keyboards and their functions?
• A: The three types are:
  • Direct Offline: Each key has a dedicated resistance-channel.
  • Ladder: Increases the number of keys.
  • Matrix: Connects to the microcontroller terminals.
• Q: How does a JVC remote control maintain contact with a TV?
• A: Each control transmits a unique identified pulse.
• Q: Which power supply is responsible for providing energy to SYSCOM?
• A: The power source.
• Q: How is TV volume controlled via the remote?
• A: It's controlled by a DC voltage amplifier that reaches a driver.
• Q: If volume is controlled from the IF stage, what is used for output volume control?
• A: PWM (Pulse Width Modulation).
• Q: Before SYSCOM and remote controls, how were color, tint, and brightness adjusted on TVs?
• A: Using PWM circuits (analog).

TV Input & Signal Processing

• Q: What component removes the color signal when a program is in black and white?
• A: It's called the color killer block.
• Q: What is the input selection stage?
• A: It involves devices that manage and enhance the video signal.
• Q: What is simulcast?
• A: It's an input stream selector circuit for specialized applications.

Modern Television Technologies

Cable Television Systems

Cable TV utilizes perfectly shielded cables, leveraging the full spectrum to offer over 100 channels (beyond the traditional 68). Modern TVs are equipped with tuners capable of handling this expanded channel count. The transmission medium increasingly incorporates optical fiber.

Digital Signal Transmission

Digital signal transmission involves digitizing TV content, which is then grouped into information packages. Specific areas within the signal are allocated for grouping TV information. Other channels undergo similar processing. It's possible to transmit up to 24 channels within a single bandwidth using an installed RF module.

Direct-to-Home (DTH) Satellite Systems

DTH systems have rapidly emerged due to technological advancements. They feature smaller antennas and offer over 100 channels. Key providers include Hughes, PanAmSat, and RCA. In DTH, the analog signal is converted into digital binary data (0s and 1s).

Plasma Television Technology

Plasma TVs are known for being lightweight and consuming relatively low power. Their display consists of a substrate surface covered with millions of tiny cells. Each cell contains neon and xenon gases and is coated with a phosphorescent substance. Plasma displays operate on the principle of luminescence. Electric fields ionize the gas atoms, causing free electrons to collide with accelerated gas atoms. These collisions excite and de-excite the gas atoms, which then produce ultraviolet (UV) radiation.