A CMOS quadrature modulator for wireless communication IC

This brief presents a CMOS digital quadrature modulator, which is based on a CMOS digital modulator and a five-level digital-to-analog converter, for wireless communication IC. In the digital modulator, a circular shift register is used to produce a continuous sinusoidal wave with different phases. With this technique, the quadrature modulator has advantages in low power consumption, small area, and expansion capability.