Howtosignalprocessing
What is 16-QAM modulation method?
16-QAM is a type of Quadrature Modulation (QAM) in which a carrier wave of a fixed frequency can exist in one of sixteen different states. This can be represented in a constellation diagram (Figure 1) where each state is a symbol that contains one of 16 different amplitude and phase levels.
How does QAM demodulation work?
In the QAM demodulation process, a balun is used to split the incoming modulated signal to allow extraction of the in-phase and quadrature components of the signal. The signals can be coherently extracted since the two components are orthogonal to each other.
How is 16-QAM signal generated?
16-QAM signals can be generated with tandem-QPSK transmitter by cascading IQ modulator, Mach-Zehnder Modulators (MZM) and phase modulators (PM) [7], or cascading two IQ modulators [8]. Such transmitters were driven by binary electrical signals, simplifying the drive electronic circuits design.
