Howtosignalprocessing
- How does QPSK modulation work?
- Why gray coding is used in QPSK?
- How to do QPSK modulation in Matlab?
- How to generate QPSK signal?
How does QPSK modulation work?
Quadrature Phase Shift Keying (QPSK) is a form of Phase Shift Keying in which two bits are modulated at once, selecting one of four possible carrier phase shifts (0, 90, 180, or 270 degrees). QPSK allows the signal to carry twice as much information as ordinary PSK using the same bandwidth.
Why gray coding is used in QPSK?
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.
How to do QPSK modulation in Matlab?
Plot QPSK Reference Constellation
Determine the reference constellation points. Plot the constellation. Reconfigure the object for bit input and plot the constellation to show the binary values of the Gray-encoded mapping. Create a QPSK demodulator having phase offset set to 0 .
How to generate QPSK signal?
The QPSK signal is generated by phase-shifting the carrier. This applies for any carrier frequency. All symbol transitions are possible. I/Q Signals of quadrature modulation.
