مبدأ نظام الأرقام الثنائية (Binary Number) .. كتاب التلفزيون الملون والعادي

Chapter Nineteen:

Remote control system, synthesized frequencies, and AFT (fine tuning) circuit
Remote-Control-Frequency Synthesis-

introduction :

Significant developments have taken place in the field of electronics in recent years - it began with the use of transistors, integrated circuits and special elements, after the use of valves shrank and then disappeared - and we may find at first glance that these developments are incomprehensible and difficult to comprehend. black) which we may not know its contents, which may include (11000) transistors or more, so it is better to focus on the function. And the general principle, leaving the internal details of the integrated circuits, and understanding the function and the overall work of any complex circuit is sufficient for the technician to follow up and detect emergency faults and repair them - and the use of a remote control in a TV set or something else, and enables the viewer to invest the device from a limited distance and turn it on or off - and choose Channel and control of color, lighting, contrast and sound.

In the control device there is a crystal element (that generates one fixed frequency), and from it the other synthetic frequencies (F.S) are generated - and in the electronic voter also the oscillator frequencies of the voter and all UHF and VHF channels are generated and transmitted with high stability.

In the modern device equipped with a small computer (UC), its circuit may be on a single chip, and it stores the exact frequencies for the various channels, and it has a page tuning loop (PLL) circuit. With these devices, the viewer can receive any station directly. It reduces the use of the Automatic Fine Tuning (AFT) circuit.

1-19 Principle of the Binary Number System:

It is the system used in logical circuits. that work on
Its basis is digital devices, timers, counters, frequency dividers, calculators and computers, as well as electronic remote control devices, electronic industrial control and others.

The digital system is based on two numbers

(zero - one) (0-1), and since semiconductor elements can be used as switches that have two positions (ON or OFF) (on or off). It is called bistable.

They are as follows: The number 0 zero represents the OFF state and is represented by the voltage of approximately zero volts (low level) and the number 1 represents the operating state ON and is represented by the voltage approximately +5 volts (high level) and with these two numbers
(0-1) Any decimal number can be represented

(Ordinary numbers used) These two numbers are called (Byte).

For example, the number 110101 in binary is equivalent to 3200401 = 53 decimal.

Example number: 75 = 1001011
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