Extended-range parallel-path RC oscillator synthesis: a state-variable approach

The letter points out the usefulness of state-variable techniques for realising the dynamics of a special class of RC oscillators which can be designed to oscillate at frequencies beyond the range constrained by the integrator time constants. By exploiting the `isotopic¿ nature of state-variable structures, such extended-range oscillators can be synthesised which retain the canonic simplicity of four-element frequency-determining networks and which can also be tuned electronically with a single control.