A sinewave oscillator is not supposed to have distortion. The diodes cause distortion.
A Wien bridge oscillator with an ordinary old light bulb for stabilization of its output amplitude has very low distortion and some that use a Jfet also have very low distortion.
A sinewave oscillator is not supposed to have distortion. The diodes cause distortion.
A Wien bridge oscillator with an ordinary old light bulb for stabilization of its output amplitude has very low distortion and some that use a Jfet also have very low distortion.
Some schemes work better than others for controlling excess amplification. And of course, the closer you can adjust the R6 to just a little excess amplification, the less the diodes have to vary their conduction current and thereby cause distortion. Anyway, it looks to me like the circuit can be modified to use some other form of feedback control if desired. The main feature of this circuit is a Wien bridge with single resistor tuning.
Which is why I usually order several at a time (8038) and get as many engineering samples as possible for pricey chips (MAX038). Then, in my retirement among all my digital and analog devices (and no processors), I have all sorts of things to play with when I didn't have time when I was younger.
Here is the one I built. It produces a square, triangle, and low-distortion sine wave. It will run from a few hertz to nearly 1MHZ. If you replace the 555 with a fast comparator circuit, you might make 2MHZ.
If you use a lamp stabilized bridge, you might have thermal problems because the ambient temperature will affect the lamp's temperature which in turn affects its resistance etc etc. If your ambient is pretty much always the same you'll probably be OK.
I saw one scheme where the output of the bridge was rectified, buffered, filtered and fed back to the lamp to maintain amplitude stability.