
A voltage-controlled function generator, which wholly consists of analog circuits, is used for the case study in this chapter. So, it is more valuable to simulate gradual failures and get their data for detecting the applicability of various diagnostic and prognosis algorithms. In addition, hard faults like open or short circuits are not usual but the gradual failures such as parameters shifting, usually happens. Since the real data are not easy to obtain, instead, simulation data can be considered. For real-time diagnosis and prognosis, various suitable intelligent algorithms are needed, and appropriate data is also needed to select and evaluate the intelligent algorithms. However, it seems an aporia concerning the methods of the fault diagnosis and prognosis for analog circuits in current status.

An electronic system generally consists of digital circuits and analog circuits. Prognostic and Health Management (PHM) is a key technology for condition-based maintenance and autonomic support, and electronic systems are one of the main application areas in PHM.
