This chapter provides an overview of a range of oscillator circuit topologies that are compatible with analog circuits designs and hence existing silicon carbide technology, before focusing on the realization of a high-temperature Colpitts oscillator, which is used to demonstrate a high-temperature prototype communication circuit. The drift of the central frequency with the temperature of silicon carbide–based oscillators is reported and described in terms of the parametric characteristics of the devices. The circuit is then expanded to enable the first silicon carbide Colpitts oscillator–based voltage controlled oscillator (VCO), which is presented as a method of enabling the closed loop control of the frequency of an oscillator over a wide temperature range. The chapter concludes with demonstrations of both the amplitude and frequency modulation of carrier waves from a circuit operating at 300°C and subsequently discussed with a view to creating a high-temperature wireless communication system.