In this work, an extension to the oscillator synthesis method using the state variable technique is presented. It is shown that using suitable block diagrams, which represent the state equations, systematic circuit realizations can be performed. The most critical steps of the presented method are the selection of the suitable characteristic equation and the derivation of the corresponding sub-circuits. The selection criteria of the characteristic equations for the realization of single resistance controlled oscillators (SRCOs) are also given. By using the extended state variable synthesis method, SRCOs employing a single current feedback amplifier (CIA) are obtained. Furthermore, a new active element, namely the differential voltage current feedback amplifier (DVCFA) is proposed for the realization of oscillators employing only grounded capacitors and new SRCOs employing this active element are presented. SPICE simulations and experimental results confirm the operation of the presented oscillators.