In this note, we are going to know about the Block Diagram of TV Remote Control or IR Remote Control of Television. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.
Author Name: Arun Paul.
Block Diagram of TV Remote Control (IR Remote Control of Television)
Nowadays, we are very much accustomed to operating TVs, VCRs, and other home appliances from a distance. All the desired operations, such as line switching ON and OFF, brightness control, volume control, and channel changing, can be performed from a distant place with the help of a remote controller.
To perform some operation, specific keys on the keyboard are pressed, and a corresponding signal is fed to the Infrared Transmitter. In the Infrared transmitter, the signal is pulse-code modulated to convert it to a pulse form. Next, this PCM signal is used to drive the Intra-red LED. IRT 1250 is the most popular chip for this purpose. This CMOS chip can accept up to 1024 commands.
At the receiver, a photo diode converts the received infrared signals into electrical signals. These electrical signals are boosted up using an infrared Pre-amplifier. The output of the Pre-amplifier is fed to the infrared decoder. The infrared decoder decodes these signals and converts them into respective commands like color change, change in brightness, contrast, increase in sound level, etc. A D/A converter is used to convert the digital commands into analog commands. SAS 1251 is a popular infrared receiver IC used in TVs and VCRs. The signals are transmitted through infrared light in the form of packaged pulses.