A continuity tester injects an AC signal into the conductors of a cable to find circuit faults. 一个连续性测试器给电缆导线注入交流信号，从而找到电路故障。
With the information and the undistorted parts, the whole spectrum can be recovered by solving the nonlinear equations, so the AC signal is also recovered. 这一先验知识结合信号中未失真的频谱部分，通过求解一组非线性方程即可近似恢复出交流信号的全部频谱，从而恢复出完整的交流信号。
