Two-frequency method for probing of ionospheric resonance inhomogeneities

The paper studies principles of ionospheric irregularities probed using polyharmonic signals on the example of the two-frequency oscillation which is a beat signal. Authors have considered the interaction of a symmetrical two-frequency signal with an abstract resonant circuit which shows the normalized frequency dependence of the reflection coefficient, typical for resonant inhomogeneities in the form of a periodic structure in the ionosphere.