What is the frequency and type of modulation used in an IR Remote

SOLUTION

IR Remote controls for TV:

• Today’s modern remote controls work by modulating the output from an infra-red LED.
• The circuit board consists of circuitry to sense the connections or detect the button being pressed and produces the signal in Morse code form which is amplified by the transistors and then given to IR LED.
• Pulse code modulation technique is used. 
• The reason for modulation is to separate the remote IR range from the IR light emitted by other bodies in the vicinity.
•  A series of pulses of varying width is sent to a gate that turns on or off, the modulator which is usually 38 kHz.