基于双路正交实现数字锁定放大器的方法

摘要

采用 IQ(正交)双路参考信号实现数字 LIA(锁定放大器)的微弱正弦信号的检测，利用稀疏分解将原子库的原子对作为参考信号，利用 MP(匹配追踪)算法来搜索过完备原子库的最优原子对，并通过该原子对判断最佳相位角，从而合成最优原子。由该最优原子可以估计得到输入有用信号，从而检测估计出输入信号中的有用正弦信号。与单路数字 LIA 相比，该方法计算效率更高，计算速度亦成倍提高，且继承了单路数字 LIA 的优点。%This paper introduces the detection of the weak sinusoidal signals of Lock-in Amplifiers (LIA)by using In-phase Quadrature (IQ)dual-way reference signals.It first uses the atom pairs of the atomic reservoir as the reference signals by sparse decomposition and searches for the optimal atom pair by using the Matching Pursuit (MP)algorithm.Then,it decides the best phase angle from this atom pair and thus synthesizes the optimal atom.From this optimum atom it obtains estimated useful input signals and detects the sine signals in the input signals.Compared with the single way digital LIA,this approach is better in computational efficiency as the computation speed is doubled and inherits the advantages of the former.