Bandwidth extension of oversampled Analog-to-Digital converters by means of gain boosting

摘要

This paper presents a novel technique to extend the bandwidth of oversampled Analog-to-Digital Converters (ADCs) when clock frequency cannot be increased and oversampling has to be preserved. The Signal Transfer Function (STF) of the converter is modified to boost the signal in the extended band. The modification keeps the noise transfer function (NTF) unaffected, and therefore, there is no need of increasing the order of the loop filter or the resolution of the quantizer. Using the proposed technique, the converter has the capability of processing input signals in the extended band with increased resolution or even in both bands concurrently, by introducing minor circuit modifications. An improvement of 6dB in the Signal-to-Noise Ratio is reached, which allows to maintain the order of the loop filter or the resolution of the quantizer, thus saving power consumption and silicon area.