Apparatus for calculating amplitude values

摘要

The amplitude value of a sinusoidal wave is calculated by operating means which processes absolute values of two data samples which are sampled from the sinusoidal wave at two points spaced 90 DEG electrical degrees apart thereby producing an electrical signal proportional to the amplitude value. The operation means comprises a comparator, a combination of an adder and a subtractor, or a combination of a comparator and an adder. The output of the comparator or the combination is multiplied with a predetermined coefficient and then added together to produce said signal.