The results of preliminary experiments into the use of adaptive quantization in a sigma-delta modulator (SDM) are described. A peak value is calculated in a block wise fashion over the signal and used to control the level of a single bit quantizer. This results in extended dynamic range at low signal levels. When used as a part of an analog-to-digital converter, the oversampling ratio or the order of the loop filter can be reduced as compared to a linear quantizing SDM.
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