إشارة تزامن الألوان (Burst) : أو دفقة الألوان .. كتاب التلفزيون الملون والعادي

3-4 Burst signal: or color splash: The Burst signal is transmitted as part of the color visual signal.

vehicle. It is necessary to obtain the correct color characteristics with the same page difference and length, and in its specific place for each color, Figure (3-10). This signal carries the same color sub-carrier frequency, which is (3.58 MHz) in the NTSC system or (4.43 MHz in the PAL system) and has the same page difference. 11 oscillations and this burst does not affect the pulses or horizontal lines, because it has a smaller amplitude than the duration of these pulses and comes immediately after it.
The color splash also has the function of keeping the page difference frequency of the local oscillator in the receiver, which has the same color sub-carrier frequency. In the SECAM system, special pulses are added to synchronize the electronic switch page, called the line assignment signal, and these pulses are sent during the vertical shutdown period, and through nine scan lines, to act as the pulse in the PAL and NTSC systems.
In the PAL system, there are identification pulses with a frequency of (78 kHz) that reach the heart of the (R-Y) axis at an angle of (180). In the SECAM system, it distinguishes (R-Y from BY), which is not present in the NTSC system because the (R-Y) axis is not inverted.

3-5 Conditions of conformity or harmony:

Since color television was developed after a long time had passed since the spread of black and white television, and the presence of a very large number of old devices - it was necessary to continue its work and investment as it was. Therefore, the designer of any colored system must take into account the process of matching and harmony between all these devices in the following respects:

1 - The possibility of receiving color programs in any old TV set with (black and white) system, in addition to receiving these programs on color TV - and in color of course - and this is achieved by sending the Y-luminance signal that carries black and white information as in Figure (11-3) - as for the signal The colored C carries information Colors .
The ability to receive black and white programs on the color device, in addition to receiving them on the monochrome TV. Without any bad effect on the image as well

In Figure (12-3) all of this called for the use of the same frequency range for the channels - the width of the field separating the carrier of the image and the sound - and loading the colored visual signal with the same horizontal and vertical synchronization pulses, equalization and erasure pulses - in addition to the color signal and its synchronization - without interference, confusion or conflict with Any station broadcasting its programs in color will be picked up by all receiving devices colored in color - and ordinary ones in black and white - just as any station broadcasting in black and white will be picked up by all colored devices in the same colors, i.e. white And black.
All 3-6 international systems in color television broadcasting: the current systems depend on analyzing images into the three primary colors (red - green - blue) (RGB). The image is analyzed with the help of color segmented mirrors and special color filters. Then the color difference signals (R-Y) and (B-Y) are transmitted in addition to the luminance or luminance signal for - and the page difference between the two difference signals
My color is (990). Then these signals are entered for processing in the coding circuit, loaded with pulses and other necessary signals, and then amplified and transmitted along with the audio signal.

via transmitting antennas.

This process is almost completely similar in all systems - and the difference is in the way color information is encoded and decoded, the modulation method and the frequency range for each of them, as we will explain. As for the reception, the process of decoding and restoring all is performed

the information .

The international systems for color television are close to thirty systems, but the systems that are widely spread in most countries of the world are:
US NTSC system.
French SECAM system
German PAL system