pccmd
Newbie level 1
sine wave notches
I'm prototyping a sine wave generator using AD8620(dual, low noise, high bandwidth(+/-) ) op amp. The 'A' side is a relaxation oscillator and 'B' side is a Sallen-Keys LPF.
Well, the first .jpg attachment herein is initial circuit(using 10uF caps. where the supply connects to breadboard(+ and - ), the top image is output of first stage and lower is the sine wave o/p. WHAT is producing the square wave's distortion AND the notches in the sine wave(did improve with the power supply filtering mentioned above) ?
Now, I put a 0.1uF cap. between output of first stage and ground, and low and behold the notches improved as in the second attachment. I understand why the 'square wave' has become triangular, but HOW did the cap. get rid(nearly) of the notches, and WHY is the frequency now so much lower?
Thank you.
I'm prototyping a sine wave generator using AD8620(dual, low noise, high bandwidth(+/-) ) op amp. The 'A' side is a relaxation oscillator and 'B' side is a Sallen-Keys LPF.
Well, the first .jpg attachment herein is initial circuit(using 10uF caps. where the supply connects to breadboard(+ and - ), the top image is output of first stage and lower is the sine wave o/p. WHAT is producing the square wave's distortion AND the notches in the sine wave(did improve with the power supply filtering mentioned above) ?
Now, I put a 0.1uF cap. between output of first stage and ground, and low and behold the notches improved as in the second attachment. I understand why the 'square wave' has become triangular, but HOW did the cap. get rid(nearly) of the notches, and WHY is the frequency now so much lower?
Thank you.
