An analog circuit fault diagnosis method using a single testable node comprises the following steps: (1) obtaining prior sample data vectors under each fault mode; (2) computing a statistical average of the prior sample data vectors under each of the fault modes; (3) decomposing a signal by an orthogonal Haar wavelet filter set; (4) extracting the feature factor of the prior sample fault modes; (5) extracting a fault-mode-to-be-tested feature factor; (6) computing a correlation coefficient matrix and correlation metric parameters between the feature factor of the prior sample fault modes and the feature factor of the fault-mode-to-be-tested; and (7) detennining a fault mode according to a maximal correlation principle by comparing the correlation metric parameters. The method can convert a single signal into a plurality of signals without losing original measurement information, and extract an independent fault mode feature factor reflecting variations of a circuit structure in different fault modes, can be used to study an associated mode determination rule and successfully complete classification of circuit fault modes.

Embodiments of the present disclosure includes a margin measurement circuit to determine margin of one or more signal monitoring circuits. Signals corresponding to voltages, temperatures, or clock signals may monitor deviation above or below trip points. Faults are triggered if the signals deviate outside a range set by the trip points. Margin between actual signal trip points and the set high and low trip points of the monitoring circuits may be measured by a margin measurement circuit. In some embodiments, the set trip points may be optimized for particular electronic system operation conditions. The present techniques may improve an electronic system's ability to detect and prevent remote or local attacks.

Embodiments of the present disclosure includes a margin measurement circuit to determine margin of one or more signal monitoring circuits. Signals corresponding to voltages, temperatures, or clock signals may monitor deviation above or below trip points. Faults are triggered if the signals deviate outside a range set by the trip points. Margin between actual signal trip points and the set high and low trip points of the monitoring circuits may be measured by a margin measurement circuit. In some embodiments, the set trip points may be optimized for particular electronic system operation conditions. The present techniques may improve an electronic system's ability to detect and prevent remote or local attacks.