Signal processing apparatus, and voltage or current measurer utilizing the same

摘要

A signal processing apparatus produces a signal representing the effective value of an inputted alternating signal. The apparatus includes a square calculator, a filter and a square-root calculator. The square calculator produces a square signal representing several squared values of the inputted alternating signal. The filter extracts a DC component signal from the square signal. The square-root calculator produces a signal representing the square root of a level value of the extracted DC component signal.