Howtosignalprocessing
- What do you mean by constellation diagram?
- Why do we use constellation diagram?
- What is QPSK constellation diagram?
What do you mean by constellation diagram?
A constellation diagram is a representation of a signal modulated by a digital modulation scheme such as quadrature amplitude modulation or phase-shift keying. It displays the signal as a two-dimensional xy-plane scatter diagram in the complex plane at symbol sampling instants.
Why do we use constellation diagram?
The constellation diagram is useful because it displays both the ideal (reference) signal and the actual measured signal on the same plot. The ideal signal locations of a constellation diagram are pre-defined generically depending on the modulation format chosen.
What is QPSK constellation diagram?
QPSK uses four points on the constellation diagram, equispaced around a circle. With four phases, QPSK can encode two bits per symbol, shown in the diagram with Gray coding to minimize the bit error rate (BER) – sometimes misperceived as twice the BER of BPSK.
