The technique of Feedback Amplitude Modulation (FBAM) is introduced in its second-order form. The basic aspects of the novel algforithm are discussed and its interpretation as a special case of a recursive time-varyring linear filter is explored. Extensions to the basic method are introduced, first with reference to existing variants of the first-order case, which have been previously studied. Second-order specific variations, such as pole-angle modulated resonator and frequency modulation, are discussed in some detail. The spectra produced with the proposed second-order methods are generally richer than those obtained using first-order methods, which is very desirable. Applications of the second-order FBAM complement the paper.