Quadrature Amplitude Modulation (QAM)
Combination of amplitude and phase modulation
Pros: transmit more bits per symbol
Cons: susceptible to noise
Phase Shift Keying (PSK)
Pros: less susceptible to noise
bandwidth efficient
Cons: requires complex receivers and transmitters
Modulation Scheme
encode info onto a carrier wave
Order of Modulation
A two-frequency FSK can also be referred to as 2FSK, a four-level or four frequency FSK would be 4FSK, finally it can be abstracted as N-level FSK.
Frequency Shift Keying (FSK)
Pros: less susceptible to noise
Cons: requires larger bandwidth/bit than ASK
Order of Modulation
Frequency Deviation
Amplitude Shift Keying (ASK)
Pros: simple
Cons: susceptible to noise
Amplitude Modulation Depth
Digital Modulation = Shift Keying
- Amplitidue Shift Keying (ASK)
- Frequency Shift Keying (FSK)
- Phase Shift Keying (PSK)
- Quadrature Amplitude Modulation (QAM)
Pulse Code Modulation (PCM)
use to convert analog signals to digital signals
- sampling
- quantizing
- encoding
Baseband + Carrier wave
The process of superimposing a low frequency signal onto a higher frequency signal
Analog Modulation
AM - Amplitude Modulation
FM - Frequency Modulation
PM - Phase Modulation
Carrier Waves
- high frequency wave used to carry the baseband signal over long distances
Baseband Waves
- original signal containing actual info
Modulation
variation of a part of an EM wave for the transmission of information
