A single-chip digital phase meter for vibration analysis of rotating machinery

The design of a digital phase meter, intended for vibration monitoring and analysis of electric power generators, is discussed. The design may be implemented in a single, field-programmable gate array, operating at 32 MHz. Inputs to the device are a trigger pulse and a sampled, bandlimited vibration signal. The device measures the phase angle of the signal at 1/2, 1 or 2 times the rotation frequency with a resolution of 1 degree, referred to the trigger signal. A novel frequency multiplier, as well as a tracking filter and zero-crossing detector are incorporated into the device. The trigger frequency range is 1 to 1000 Hz. A detailed error analysis, as well as experimental results, are presented.