Consider the oscillator circuit shown in the figure. The function of the network (shown in dotted lines) consisting of the $100 \: k \Omega$ resistor in series with the two diodes connected back-to-back is to:
- introduce amplitude stabilization by preventing the op amp from saturating and thus producing sinusoidal oscillations of fixed amplitude.
- introduce amplitude stabilization by forcing the opamp to swing between positive and negative saturation and thus producing square wave oscillation of fixed amplitude.
- introduce frequency stabilization by forcing the circuit to oscillate at a single frequency.
- enable the loop gain to take on a value that produces square wave oscillations.