Twin-T oscillators can be used to produce sinusoidal signals in the audio track with good performance. The circuit shown in the figure is an example of a double T oscillator for the audio track using an operational amplifier type 741. The double T components determine the operating frequency of the oscillator at the same time as the 100k-ohm potentiometer in the reference circuit it determines the symmetry of the generated signal and therefore its distortion. Note that the power supply must be symmetrical and that the output is made through a 1uF capacitor. Depending on the application and the frequency range, this capacitor can be changed or even eliminated.
