Modulaatioviestin

Modulaatioviestin, a Finnish term, translates to "modulation message" or "modulated signal" in English. It refers to a signal that has been altered in some way to encode information. This alteration, known as modulation, is a fundamental process in telecommunications and signal processing.

The primary purpose of modulation is to transmit information efficiently and reliably over a communication channel. This is often necessary because the original information signal, such as voice or data, may not be suitable for direct transmission over the intended medium. For example, low-frequency audio signals cannot travel long distances through the air, whereas higher frequency radio waves can.

Modulation involves changing one or more properties of a carrier wave (a high-frequency signal) in accordance with the message signal. Common modulation techniques include amplitude modulation (AM), where the amplitude of the carrier wave is varied, and frequency modulation (FM), where the frequency of the carrier wave is varied. Phase modulation (PM) is another method, altering the phase of the carrier wave.

The choice of modulation technique depends on factors such as the desired bandwidth, noise immunity, and the characteristics of the transmission channel. After modulation, the signal can be transmitted, and at the receiving end, a process called demodulation is used to extract the original message signal from the modulated carrier wave. This allows for the recovery of the information that was initially encoded.