高动态GNSS信号多普勒模拟任意阶DDS合成器设计*

为高精度模拟高动态条件下GNSS信号的多普勒特性，本文提出一种任意阶DDS信号合成器的设计方法。设计了任意阶DDS信号合成器的结构；通过理论分析，推导了各级累加器相位初值的计算公式；给出了字长选择方法；经仿真与验证，该方法能精确模拟GNSS信号的多普勒特性。此外，本文提出的DDS设计方法不受阶数的限制，可普遍应用于各类信号模拟器的设计。

Design of Any-Order DDS Synthesizer for High-Dynamic GNSS Signal Doppler Simulation

In order to accurately simulate the Doppler characteristics of high dynamic GNSS signals, we propose a method for designing any-order DDS synthesizer. An any-order DDS synthesizer structure is designed; By using theoretical analysis, we derive a formula for calculating the initial phase of every accumulators in DDS synthesizer, and develop a technique to determine the DDS word length. Finally, simulations are performed to validate the proposed method, which can accurately simulate the Doppler characteristics of GNSS signals. In addition, since the proposed method for designing DDS synthesizer has no order limitation, it can be widely used in different types of signal simulator.