Abstract: A hand-held apparatus gathers and analyzes test data associated with rotating electric machines, where the test data is indicative of one or more operational characteristics of the mechanical equipment. The apparatus, which is operable to be carried by an operator from one machine to another along a test route, includes a sensor input port for receiving a sensor signal from a sensor, where the sensor signal is indicative of one or more operational characteristics of the rotating electric machines. The apparatus also includes a signal conditioning circuit for receiving the sensor signal, and for conditioning the sensor signal to produce a conditioned signal which is appropriate in format to be digitally processed. A processor, which is coupled to the signal conditioner, receives and processes the conditioned signal according to processing instructions and processing parameters to produce a test spectrum. The processing parameters determine one or more characteristics of the test spectrum.