استخدام جهود التحكم .. كتاب التلفزيون الملون والعادي

Use control efforts:

The work of all the circuits in the remote control system is similar, as each control function has a special signal with a specific frequency, which is generated when pressing its compressor, then received, enlarged, distinguished and memorized in the same way. As for the source of the control voltage, which is taken from the resistance (10000 ohm) Its use varies from one control function to another.

In the process of turning on and off (ON OFF), the control voltage occupies a part of the flip flop circuit, which operates the relay as in Figure (28-19). As for the sound, it is adjusted by changing the bias of two stages of the amplification of the audio signal, as in Figure (19). - 29). As for the color control method, it depends on controlling a controlled amplifier that generates the reference color frequency signal.

As for changing channels, it is done by controlling the movement of a DC motor and its relay. Table of remote control frequencies according to the Quasar system:

1 - Volume up + on control function, frequency 38.50 kHz.

2 - Volume down + off control function, frequency 44.50 kHz.

18-19 Remote control system (with direct control):

The system is remotely controlled using an infrared transmitter and receiver. The figure shows a model of the remote control device (transmitter), which contains (16) staplers or compressors, and the power source is a 1.5 volt battery or more. Compressors from (0) to (9) directly select the channel, and there is a seek up and seek down compressor - the volume up and the volume down. And press audio - silence (Audio Mute). And a pressure switch on and off (ON OFF) and a diode (Led) that lights up when any button is pressed to indicate that the control command has been entered into the device.

The sound canceling button hides the sound when pressed directly. The sound returns to its previous level when pressed again.

The used channel can be restored by pressing pushbutton number (9), and the channel number appears on the screen for (6 seconds).

And since the device works in infrared, it requires directing the front of the transmitting device towards the front of the TV set directly - and this is what makes this system protected from jamming and interference signals.