  This paper introduces a waveform design method using Multi-Tone Feedback
Frequency Modulation (MT-FFM), a generalization of the single oscillator
feedback FM method developed by [Tomisawa, 1981]. The MT-FFM utilizes a
collection of $K$ harmonically related oscillators each governed by a design
parameter $z_k$ which are utilized as a discrete set of parameters that may be
modified to generate a richer set of modulation functions than in the single
oscillator case. The resulting modulation function is represented using a form
of Kapteyn series composed of Generalized Bessel Functions. This paper
describes the structure of the MT-FFM waveform, derives the Kapteyn series
representation of the waveform's modulation function, and demonstrates the
design method with a waveform design example.
