基于DDS的任意频谱信号重构与数字正交调制方法

任意频谱信号产生方法是将功率谱转换为矢量频谱，再经傅立叶反变换，对得到的多个时域数据序列进行加窗、搭接得到一个长的时间序列，用该序列去逼近任意频谱信号对应的时域无限长序列，最后经过数字正交调制重构出任意频谱信号。计算机仿真分析表明，本文方法的理论重构精度达80dB以上，通过直接数字频率合成技术（DDS）实现的数字正交调制器的实际输出信噪比达65dB以上。

The Method of Reconstructing Optional Spectrum Signal and Digital Quadrature Modulation Based on DDS

Optional spectrum signal reconstruction, digital quadrature modulation and the fast algorithms are discussed.The method of reconstructing optional spectrum signal is converting power spectrum to vector spectrum, operating inverse Fourier transform, windowing and overlapping the series time domain sequence to generate a long time domain sequence, which approximates the infinite sequence of optional spectrum signal, and then performing digital quadrature modulation to reconstruct the optional spectrum signal. The computer simulation indicates that the theoretical reconstruction accuracy of the method is over 80 dB, the actual ratio of signal to noise of the digital quadrature modulator implemented by direct digital frequency synthesis (DDS) is over 65 dB.