自适应Sigma-Delta A/D转换器的设计

The Design of Adaptive Sigma-Delta A/D Converter

对于传统的Sigma DeltaA/D转换器 (ADC) ,其信噪比 (SNR)将随着输入信号强度的减小而降低 .因此 ,本文根据自适应理论提出一种自适应ADC的解决方案及相应的电路实现 .在充分考虑了在电路实现中误差的存在 ,给出了误差自校正电路 .仿真结果表明 ,这种自适应ADC的SNR几乎与输入信号的强度无关 .

The signal to noise (SNR) of conventional sigma delta analog to digital converter (ADC) reduces with input signal strength.The existing concept of adaptive quantization is applied to the design of ADC to improve SNR with high dynamic range.An adaptive algorithm and its circuit implementation is proposed.Because of the error due to the circuit implementation,we also designed the error self-calibration circuit.Simulation results indicate that SNR can be nearly independent of the signal strength.