A signal measuring/diagnosing system and method, and methods and systems in which the same are applied to individual devices, which are capable of measuring and diagnosing a target signal. A first exemplary embodiment of the present invention provides a signal measuring/diagnosing system that measures and diagnoses signals of a target system, including: an analog/digital converter that converts analog signals of the target system into digital signals and corrects the converted digital signals; a signal pre-processor that sets analysis target frequency bands so as to selectively store signals, analyzes target frequencies and frequencies for each band, and determines a failure of the target system based on the analyzed frequencies; a local server that selectively stores data and signals transmitted from the signal pre-processor, diagnoses a state of the target system based on the transmitted data and signals, and communicates with an external device.