An amplitude-stabilized bridged-t oscillator

In an analog computer application which used several nonlinear elements, there arose a need for a sinusoidal oscillator of 2,500 cps (cycles per second) frequency, with frequency stability of better than 0.5%, amplitude stability greater than 0.2%, and a harmonic content of less than 0.2%. There are very few circuits which can reconcile these requirements, one of these being the Meacham oscillator.1 If the requirement is for an oscillator in the audio-frequency range, the Meacham circuit loses its attractiveness, since quartz crystals in this frequency range are rather cumbersome. If an inductor and a capacitor are substituted for the crystal, it is found that some other circuits have better inherent phase magnification.