Modulation
- Modulation
- Modulation is the process of modifying one or more parameters of a base communications signal such as frequency, phase, amplitude, or simply the presence and absence of the signal, for the purpose of encoding information into the signal and transmitting it to a destination.
Modulation is described as being performed at the physical layer of the OSI Model. The carrier signal can be an electrical current, a radio or microwave frequency or light. The process of modulation of the data also requires demodulation at the receiving end.
There are a number of modulation techniques:
- Return to Zero
- Non-Return to Zero
- Pulse Code Modulation (PCM)
- Phase Shift Keying (PSK)
- Frequency Shift Keying (FSK)
- Amplitude Shift Keying (ASK)
- Quadrature Amplitude Modulation (QAM)
- Manchester Encoding
- Differential Manchester Encoding
- Alternate Mark Inversion (AMI)
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