8-PSK modulation basics or multilevel PSK modulation which is a type of digital modulation based on carrier phase change.
In Phase Shift keying modulation or PSK modulation phase of carrier is changed according to the digital data. It is digital modulation technique. It is used in broadcast video systems, aircraft and satellite systems.
We can achieve bandwidth efficiency when we represent each signal element to map more than one bit.In BPSK modulation digital data of 1 and 0 is represented by 180 degree phase change. In QPSK by phase shift of 90 degree, here 2 bits are mapped on each signal. In Multilevel PSK more than 2 bits are mapped using different phase angles. In 8-PSK eight different phase angles are used to represent bits, here 3 bits. Figure below shows constellation of 8-PSK signal.
Eight Phase Shift Keying (8PSK) is a method to transmit digital information on a carrier by changing the phase of the carrier. In 8PSK there are 8 different phase changes defined, each phase change represents the transmission of 3 bits. 8PSK is used in e.g. EDGE.
The phase changes are: 0, 45, 90, 135, 180, 225, 270 and 315 degrees.