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Figure 1-16.—Sine-wave generators with a combination of impedances. | Up
Neets Module 12-Modulation Principles | Next
SPECTRUM ANALYSIS |
1-24
Figure 1-17 illustrates the relationship between the two frequencies (10 and 11 hertz). Since the
waveforms are not of the same frequency, the 10 hertz of view (B) and the 11 hertz of view (A) will be in
phase at some points and out of phase at other points. You can see this by closely observing the two
waveforms at different instants of time. The result of the differences in phase of the two sine waves is
shown in view (C). View (D) shows the waveform that results from the nonlinearity in the circuit.
Figure 1-17A.—Frequency relationships.
Figure 1-17B.—Frequency relationships.
Figure 1-17C.—Frequency relationships.
Figure 1-17D.—Frequency relationships.
The most important point to remember is that when varying voltages are applied to a circuit which
contains a nonlinear impedance, the resultant waveform contains frequencies which are not present at the
input source.
The process of combining two or more frequencies in a nonlinear impedance results in the
production of new frequencies. This process is referred to as heterodyning.
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