Signal, as a waveform, is the carrier of data. By alternating amplitude, frequency, phase, or any combination of them, the modulation process synthesizes the signal (as the carrier wave) and the data (as an input wave) and generates the modulated result. Modulation can be analog or digital.
There are many types of digital modulation techniques, for example:
- ASK – Amplitude Shift Keying
- FSK – Frequency Shift Keying
- PSK – Phase Shift Keying
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