Amplitude stabilization in a triangular wave quadrature oscillator

The application of phase plane concepts far designing quadrature oscillators is a well-known technique in the field of sine, square or triangle wave generators. The simple circuits that have been reported as triangular generators [1]-[2] are based on conservative equations that do not describe the starting transient and the amplitude stabilization. In this paper the slew-rate of the operational amplifier and the limited output voltage of the integrator that performs the circuit implementation, are shown to be responsible for the starting and the stabilization of the waveform generators.