Figure 1-16.—Sine-wave generators with a combination of impedances.

1-23 combined linear and nonlinear impedance circuit, the voltages developed across the impedances are complex waveforms. Figure 1-16.—Sine-wave generators with a combination of impedances. When two sine wave voltages are applied to a circuit, as in figure 1-16, nonlinear impedance Z2 reshapes the two sine-wave inputs and their harmonics, resulting in a very complex waveform. Assume that nonlinear impedance Z2 will allow current to flow only when the sum of the two sine-wave generators (G1 and G2) has the polarity indicated. The waveforms present across the linear impedance will appear as a varying waveform. This will be a complex waveform consisting of: · a dc level · the two fundamental sine wave frequencies · the harmonics of the two fundamental frequencies · the sum of the fundamental frequencies · the difference between frequencies The sum and difference frequencies occur because the phase angles of the two fundamentals are constantly changing. If generator G1 produces a 10-hertz voltage and generator G2 produces an 11-hertz voltage, the waveforms produced because of the nonlinear impedance will be as shown in the following list: · a 10-hertz voltage · an 11-hertz voltage · harmonics of 10 hertz and 11 hertz (the higher the harmonic, the lower its strength) · the sum of 10 hertz and 11 hertz (21 hertz) · the difference between 10 hertz and 11 hertz (1 hertz)