Method of measuring power-system frequencies

摘要

A method of frequency measurement is described which uses a combination of digital and analogue techniques and is particularly suitable for measurements in the range 20????????500 Hz. An analysis is made of the errors inherent in the method. The design of a frequency meter covering the range 46????????51 Hz with a long-term accuracy within 0.05 Hz is given: a quartz crystal is used as a reference standard, and the frequency is displayed on a moving-coil meter. The design can readily be adapted for a different frequency range.