Nyquist frequency signal, whereas "Nyquist frequency" is a property of a discrete-time system. When the function domain is time, sample rates are usually expressed in samples per second, and the unit of Nyquist frequency is cycles per second (hertz). When the function domain is distance, as in an image sampling system, the sample rate might be dots per inch and the corresponding Nyquist frequency would be in cycles/inch. Referring again to Figure 1, undersampling of the sinusoid at 0.6 f is what allows there to be a lower-frequency "alias", which is a different function that produces the same set of samples. That
Per-unit system this, the base currents I and I are related in the opposite way that V and V are related, in that formula_31 The reason for this relation is for power conservation S = S The full load copper loss of a transformer in per-unit form is equal to the per-unit value of its resistance: formula_32 formula_33 Therefore, it may be more useful to express the resistance in per-unit form as it also represents the full-load copper loss. As stated above, there are two degrees of freedom within the per unit system that allow the engineer to specify any per unit