The process of applying a signal onto a carrier signal.
Modulation is done to enable the transmission of information over long distances and through various media. By converting a low-frequency data signal into a higher-frequency carrier signal, modulation allows signals to:
- travel efficiently
- reduces interference
- share the same transmission medium (multiplexing)
It also helps match the characteristics of the transmission channel, improving reliability and signal quality.
Carrier signal
A high-frequency continuous signal. Usually sine wave is used. Enables efficient long distance data transmission
Modulation rate
Aka. baud rate. Rate at which the signal level is changed. Measured in bauds per second.
Mark
A signal element that represents a binary 1.
Space
A signal element that represents a binary 0.
Types
Analog Modulation
Digital Modulation
Used for transmitting digital data. Common digital modulation techniques include:
- Amplitude Shift Keying (ASK)
- Frequency Shift Keying (FSK)
- Phase Shift Keying (PSK)
- Quadrature Amplitude Modulation (QAM)
Each type of modulation has its own advantages and is chosen based on factors like noise resistance, bandwidth efficiency, and complexity.