مبدأ التلفزة الملونة .. كتاب التلفزيون الملون والعادي

2-2 Principle of color television:

The principle of sending and receiving a color image is based on several elements, starting from the color television camera, which analyzes the colors of each part of the image into its three primary colors (red - green - blue) and converts them into electrical signals and then carries the appropriate modification method on high-frequency radio waves attached to the signals. The synchronous pulses are then transmitted through the transmitting antennas in a manner similar to a radio broadcast

The screen is clear and the image is divided into a large number of elements. The higher the number, the clearer the picture. And in the screen valve of the receiving device - the three-projectile MSM beam returns the same information and colors that were transmitted by the station, and this requires that the signals be large, clear, and low in distortion. As possible.
Principle of the television camera (television camera): The color television camera consists of three tubes of primary colors (Fig. Depending on the thickness and transparency of the dielectric film, the color selectivity changes and turns into a monochromatic red-green-blue luminescence.The camera also includes deflection coils, beam scanning generators, and visual signal preamplifiers, Figures (2) - (8) and (2) - ( 9) Show the principle and elements of the TV camera, that the voltage coming out of each tube is proportional to its color changes, which is one of the three primary colors, and some cameras contain a fourth tube dedicated to imaging information.

Related to black and white television, and we will explain some modern television cameras due to their importance and common use in shooting video films and others
2-3 Television cameras with solid elements: The old television cameras operate with vacuum valves that consume a large amount of electrical energy to heat the filaments, thus spreading high heat that is added to the heat generated by the lighting of imaging rooms. These machines may have to be stopped
And the lights for some time to return to their normal temperature for fear of failure of the electronic circuits in these devices and to protect them. Transistors and integrated circuits (called solid elements) have been replaced in modern imaging devices, as in the circuits of other devices. Assembled on multiple panels (Module) easy to disassemble and install. Each panel represents one or more independent circuits that are easy to disassemble, repair, or replace directly at the machine.

Types of TV cameras:

There are two basic types of television cameras:

1- The first type contains one imaging tube, and the second type contains three imaging tubes.

Television cameras are distinguished from each other in basic specifications, such as:

A - The optical shift estimated in nanoamperes (nA) and represents the camera's yield - which is the change in the intensity of the output current to the change of the light shining per square inch. And ranges from

(200 to 400 nm.

b - Darkness or dimming current - This is the amount of current that passes through the elements when dimming

complete, preferably in a small amount as possible.

C - The duration of the image on the tube plate after the absence of the photographed scene. where

It is known that the effect of the image does not disappear immediately after its absence - and this time varies

Depending on the type of elements used - and if this time is prolonged, it weakens clarity

Image. There are other specifications in terms of feeding efforts - dimensions - weight - and working temperature. ...