Why modulate analog signals?
- Higher frequency can give more efficient transmission
- Permits frequency division multiplexing
There are several ways to map Analog data to analog signals. Some of them are:
- Amplitude modulation (AM), in which the amplitude of the carrier waveform is varied over time
- Frequency modulation (FM), in which the frequency of the carrier waveform is varied in small but meaningful amounts
- Phase modulation (PM), in which the phase of a periodic carrier signal is changed
