A digital modulator with bandpass delta-sigma modulator

A digital quadrature modulator with a bandpass ΔΣ-modulator is presented that interpolates orthogonal input carriers by 16 and performs a digital quadrature modulation at carrier frequencies f_s/4, -f_s/4, (f_s is the sampling frequency). After quadrature modulation, the signal is converted into an analogue IF signal using a bandpass ΔΣ modulator and a 1-bit D/A converter. The die area of the chip is 5.2 mm² (0.13 μm CMOS technology). The total power consumption is 139 mW at 1.5 V with a clock frequency of 700 MHz. (D/A converter full-scale output current 11.5 mA).