modulaatordemodulaator

A modulatordemodulator, commonly known as a modem, is a hardware device that modulates an analog carrier signal to encode digital information, and also demodulates the signal to decode the transmitted information. This process allows digital data to be transmitted over analog communication channels such as telephone lines. The term modem is a portmanteau of the words modulator and demodulator.

The modulation process involves impressing the digital data onto an analog carrier wave. Different modulation techniques exist, such as Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), and Phase Shift Keying (PSK), each varying the carrier signal's amplitude, frequency, or phase, respectively, to represent the digital bits (0s and 1s). The demodulation process is the reverse, where the modem receives the analog signal and extracts the digital information by detecting these variations.

Modems were crucial for early internet access and dial-up networking. They convert the digital signals from a computer into analog signals that can travel over telephone lines, and vice-versa for incoming data. Over time, modem technology has evolved significantly, with speeds increasing dramatically and new transmission methods like DSL (Digital Subscriber Line) and cable modems becoming prevalent, though the fundamental principle of modulation and demodulation remains. Modern modems often integrate routing and networking capabilities.