How does a Remote Control Function?

Pulse Code Modulation

Aims:

· In which way is the information (e.g. the channel you want) transported by the infrared light?

· Compare the waveforms when you press different buttons on the remote control (e.g. channel 1 « channel 2). Try to find out what they have in common and what is different. Write down you results.

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· Physicists speak about “pulse code modulation” when they describe this phenomenon. This way of modulation is getting more and more important in the digital transmission of information.

· Look at the form of the signal an auto focus camera sends out, when it measures the distance between camera and object. Just hold the camera so that it focuses on the IR-sensor and press the release button half way.

· Take an IR-based computer keyboard, aim at the IR-sensor and watch the signal!

List of Materials:

· one oscilloscope

· one remote control

· one IR-sensor

· one auto focus camera

· one IR-based computer keyboard