10.4: A 1.75GHz Highly-Integrated Narrow-Band CMOSTransmitter with Harmonic-Rejection Mixers

The increasing demand for small-form-factor, wireless devices motivates research on highly-integrated, low-cost transmitters [1]. This work describes techniques that potentially allow implementation of the transmitter at higher levels of integration than previously achieved. A prototype CMOS IC for a narrow-band PCS system operating at 1.75GHz includes two baseband signal paths, an image/harmonicrejection upconversion mixer, a channel-selection IF synthesizer, a fixed-frequency RF synthesizer, and two quadrature generation circuits (Figure 10.4.1). The baseband signal path consists of two 10b resistor-string DACs and two 3-order Sallen & Key low-pass filters.