ICS564 Loop demo through PCI data path. DAC in Quadrature Upconverter mode .

正交脉冲计数芯片的中文说明，适合三相电动机，绞车等对两路正交脉冲信号进行加减计数的应用-Quadrature pulse counting chip Chinese explanation for three-phase motors, winches, etc. on two orthogonal pulse signal subtraction counting applications

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).