5-3 Figure 5-1.—Antenna current increase with amplitude modulation. The use of this formula is based on the assumption that the modulating voltage is a pure sine wave. Normal broadcasting, however, is characterized by complex envelope patterns, as illustrated in figure 5-2. In this light, the previous formula is not so clear. Consequently, the preceding formula should be viewed more correctly as the PERCENTAGE OF POSITIVE PEAK MODULATION. When the minimum voltage (E_{min}) rather than the peak voltage (E_{max}) is used to compute percentage of modulation, the computed percentage (shown below) is the PERCENTAGE OF NEGATIVE PEAK MODULATION: