QPSK调制的WCDMA信号的一种数模混合型解扩方法

从降低解扩电路功耗和提高运算速度两方面考虑,针对采用QPSK调制的宽带码分多址(WCDMA)信号,提出了一种数模混合型解扩方法。该方法采用二阶采样保持技术对QPSK信号进行时域离散化和正交分解,通过数字控制的模拟匹配滤波器组在模拟域进行相关运算。给出了二阶采样参数的选取原则和模拟匹配滤波器组的实现结构,通过仿真实验验证了该方法的有效性。与全数字的解扩方法相比,该方法无需高速A/D转换器和正交解调器。

New mixed analog-digital algorithm for despreading of QPSK modulated WCDMA spread-signals

To reduce the power dissipation and improve the operation speed, a new mixed analog-digital algorithm for despreading of QPSK modulated WCDMA signals is presented. In this algorithm, the spreading IF bandpass signal is directly sampled and held with the second-order sampling technique, then despread by analog matched filters which is implemented by digital-control analog parallel operational circuits. The results of computer simulation show that this despreading method is feasible. The selecting qualification of sampling parameters and implementing architecture of analog matched filter bank are given. Compared to that with purely digital matched filters, the proposed algorithm does not need two high-speed analog-to-digital converters and the quadrature demodulater.