直接序列扩频接收机最优量化器设计

通常的ADC量化分析模型均基于均匀量化器，并忽略前端抗混叠滤波器的影响。针对扩频接收机伪随机码相关特性，建立一种新的最优量化器模型，整体考虑前端滤波器的影响，同时适用于均匀和非均匀量化器的设计。理论和仿真结果表明:当采样率满足奈奎斯特定理时，滤波器损耗和量化损耗可分离；在此基础上，利用极值理论直接推导出最优量化损耗计算公式及其最优量化值的解析解。最后，以数值形式给出量化损耗随量化字长、量化电平的变化关系，可用于指导直扩接收机的工程设计。 

Design of Optimal Quantizer in DSSS Receiver

The mathematical model about the quantization of ADC are usually based uniform quantizer, and the effects of the front anti-folding filter is always ignored. the correlation characteristics of the pseudo-random code in spread spectrum receiver, an universal quantization model and theoretical formula of quantization loss is established , which can be applied to uniform and non-uniform quantization. When the filter is neglected, the quantization formula can be predigested to a more straightforward form. Numerical result show that the loss incurred by the front filter and that by quantization can be separated when the front filter is ignored and sampling rate is equal to the Nyquist rate. Finally, numeric results are listed, which can be used to direct the design of DSSS receiver.