【作者】 刘芬；

【导师】 潘明海；

【作者基本信息】 燕山大学 ， 电路与系统， 2004， 硕士

【摘要】 正交采样技术可以保留信号复包络的幅度、相位等信息，因此在信号处理领域中有着广泛的应用。传统的正交采样方法采用模拟电路来实现正交双通道处理，用这种方法获得的双路正交信号存在较大的相位误差和幅度误差，反映在频域是附加了镜频分量，因此很难满足高性能信号处理技术的要求。解决的方法是采用数字正交采样法，即对低中频带通信号直接采样并通过数字信号处理的方法来得到正交双路信号。本文对直接中频采样实现正交相干检波的方法，分析了其基本实现原理，并用统一的观点解释了基于此提出的各种方法，其中包括：低通滤波法、希尔伯特滤波法、插值法、多相滤波法、频域法；对于每一种方法的基本原理和算法都作了分析，给出了计算机仿真结果；还比较了各种方法的性能指标及适应条件。理论分析和仿真结果证明，数字正交采样技术完全可以满足高性能信号处理的要求。本文在理论分析的基础上对频域法进行了改进，给出了一种适于DSP编程实现的方法，该方法可提高运算的精度和实时性。本文还探讨了数字正交采样技术在R、L、C元件参数测量中的应用，对分立元件参数测量系统提出了测量算法和硬件实现方案。该系统具有测量范围宽、可自动转换量程、测量精度高等特点，它将成为研制、生产和维修各种电子设备的有力工具。更多还原

【Abstract】 Quadrature sampling technique is widely used in the field of signal processing since it can reserve all information about the complex envelope of IF signal. When it is realized by using the analog circuits, the conventional quadrature sampling method may result in the large image frequency errors. So it is very difficult for the classical method to satisfy the requirement of high performance signal processing technique. The solution of this problem is to use the digital quadrature sampling, that is, the direct sampling of low IF (Intermediate Frequency) bandpass signal and through digital filter to get quadrature signals. In this paper, the elementary implementation principle is analyzed for the new method that realizes quadrature coherent detection by direct sampling of IF signal. And all the implementation methods up to now which include low-pass filter method、Hilbert filter method、interpolation method、polyphrase filter method and frequency field method are interpreted from the united view. The elementary principles and the implementation process for each method and concludes from simulation results to compare their features and application conditions that the new approach can satisfy of the requirements of high performance signal processing technique. Based on the theory analysis, a new approach is presented. The proposed approach improves the ability of real-time processing and makes the frequency field method perfect. The paper also discusses the application of this technique on RLC parameter measurement and the hardware scheme is given.更多还原