Basic principle: Readings present the productive voltage determined by the average price of samples about an entire range of periods of the basic frequency trong m?t kho?n th?i gian nh?t ??nh tr??c khi ?i?u ch?nh, t?t nh?t b?n nên dùng ph??ng pháp t? ??ng ho?c xây d?ng hàm ?? ki?m tra v?i d? li?u.You will find an attractive benefit propositio