Direct Digital-to-RF Conversion for Mobile-Phone BasestationApplications using Bandpass Sigma Delta Modulation

Sigma-delta modulator based digital-to-analog converters (DAC) have offered low-frequency designers a highly linear, high resolution data converter architecture that is highly amenable to integration with complex digital systems. Increasingly these data converters have been used to deliver all the power needed. In wireless applications, it is increasingly desirable to apply low-frequency sigma-delta techniques to RF signals and try to achieve similar benefits. In this paper we discuss the unique challenges that DACs in mobile phone basestations must satisfy and we present a flexible bandpass sigmadelta modulator architecture that can satisfy these criteria.

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