Читать книгу Handbook of Microwave Component Measurements - Joel P. Dunsmore - Страница 35

This pattern of increasing power as the input power is increased, but to the slope related to the order of the harmonic, cannot continue indefinitely or the harmonic power would exceed the fundamental power. While theoretically possible, in practice the harmonic power saturates just as the output power does and never crosses the level of the output power. However, if one uses the lower power regions to project a line from the fundamental and each of the harmonics, they will intersect at some power, as shown in Figure 1.6. The level that these lines converge is called the intercept point, and the most common value is the second‐order intercept (SOI), and intercept points beyond third order are seldom used.

There is sometimes confusion in the use of the term SOI; while it is most commonly used to refer to the second harmonic content, in some case, it has also been used to refer to the two‐tone SOI, which is a distortion product that occurs at the sum of the two tones. Most properly, one should always use the term two‐tone SOI if one is to distinguish from the more common harmonic SOI.