Would somebody be able to explain modulation and demodulation? Thanks
You have some information you want to transmit, and it's in the form of a low-frequency wave. We'll call this the
signal.
You know that a low frequency signal wont make it very far if you try to transmit it through a wire or the air, or something, so you want to encode your information onto a high frequency wave that we'll call the
carrier. This might be a light wave, for example. The modulated wave wont suffer as much of a loss when transmitted over a distance, so your information goes further.
Modulation is the process of encoding the information into the carrier wave, and in VCE physics we talk about intensity/amplitude modulation which means we encode the changes in signal into changes in amplitude of the high-frequency carrier. (there's also frequency modulation where changes are mapped onto changes in frequency).
Demodulation is the reverse process, where the information is extracted from the modulated wave (after transmission), so basically you read the changes in amplitude of the incoming wave and
that's your signal.