Putting the "FLEX" in flexible mobile wireless radios - A wideband continuous-time baudpass sigma-delta ADC software radios

This article has provided a brief overview of the SigmaDelta ADC conversion technologies for SDRs. The wireless receiver challenges were identified, the ADC design considerations and SigmaDelta solutions were discussed, and a low-distortion CT BP SigmaDelta modulator architecture was presented. The article has shown that the proposed CT BP SigmaDelta modulator is suitable for implementing high-IF ADC, making possible the software radio in handhelds. The major challenges in implementing such a high-IF ADC are the power dissipation and the degree of configurability, programmability, and adaptability that can be achieved by applying digital tuning and adaptive calibration

Wireless Receiver Challenges

A flexible radio receiver should be able to cope with a wide range of communication standards and signal bandwidths. It should adapt to the environment to optimize the power dissipation and performance according to the needs and quality-of-service (QoS) requests of the customer.