Constellation Diagrams - Digital To Analog Conversion and Transmission Tutorials Part V

A constellation diagram helps us to define the amplitude and phase of a signal when we are using two carriers, one in quadrature of the other.
The X-axis represents the in-phase carrier and the Y-axis represents quadrature carrier.

Concept of a constellation diagram(See Pic Above)

Further Reading suggested :

Digital To Analog Conversion and Transmission Tutorials Part I (D2A Conversion Introduction)

Amplitude Shift Keying (ASK)

Frequency Shift Keying (FSK)

Phase Shift Keying (PSK)

Problem Example - 1
Show the constellation diagrams for an ASK (OOK), BPSK, and QPSK signals.

Solution

Figure below shows the three constellation diagrams.

Three constellation diagrams


Constellation diagrams for some QAMs