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Center for Scientific Computation and Mathematical Modeling

Research Activities > Programs > Oversampling and Coarse Quantization for Signals > Joe Jensen

Oversampling and Coarse Quantization for Signals

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Continuous-Time Modulators for RF Applications


Dr. Joe Jensen

Ultra-High Speed Circuits Deptartment at HRL Laboratories LLC.

Abstract:   We present the status and challenges of continuous-time ΣΔ modulators for RF applications. The paper includes operation principals, state-of-the-arts, and future prospects of this essential ADC technology for high-resolution and high dynamic range. Improvements in semiconductor technology and oversampled ADC converters are provide the capability to move the digitization process forward in the signal path of RF system and perform more receiver functions in the digital domain. Continuous time design approaches for oversampled ADC can provide higher frequency operation over the conventional discrete time design approaches. Tunable bandpass loop filter implementations provide the opportunity to digitize at IF or RF. We will discuss circuit design techniques for active GM-C bandpass loop filter for high dynamic range applications. Multi-bit approaches are need for wider bandwidth applications. Multi-bit noise shaped oversampled converter require techniques for feedback DAC error correction. We will show demonstrated techniques for bandpass mismatch shaping of DAC errors to reduce DAC quantization noise.