The architecture and performance of an interpolative bandpass A-to-D converter (ADC) and digital quadrature demodulator dedicated for digital narrow-band transmission systems, like the cellular radio mobile receiver, are presented. A prototype version has been implemented on a 1.2-µm/7-GHz BiCOMS analog/digital array. A bandpass signal centered at 6.5 MHz with 200-kHz bandwidth is demodulated and converted with a 55-dB signal-to-noise ratio giving 9-b performance.