Oscillators Improvement

Recently I've been trying to come up with the perfect oscillator and there are always imperfections in the output wave. Some times it's completely indistinguishable whether it's a sine wave or something else. That's because phase shift oscillators for instance are easy. Just resistors and capacitors. As you go up the frequency ladder at some point you just have to use inductors and capacitors. That's where it gets tricky. No matter how hard you try short of using complex bandpass filters nothing else seems to work. Then i thought...where is the cleanest signal in the whole circuit?The most harmonicless one? In the tank circuit of course. Then it hit me. Why the f#ck can't i tap directly to the LC tank circuit and get a high fidelity output? I decreased the resonant output through a voltage divider and ran it through a buffer stage and there it was. The purest of them all :D...well at least a lot purer than the one the oscillator itself was offering. This can be applied to almost any kind of oscillator. You should always seek to tap into the resonant circuit if you want best results. That goes for phase shift oscillators LC oscillators of any type. The only one that'll be tricky to apply this to is the wien bridge oscillator because it is way more fine tuned circuit than this and should not be taped directly in the RC circuit as you may disrupt the gain and either stop the oscillations or bring them to cut off distortion. Oh almost forgot you may be wondering why are there two grounds seemingly disconnected from everything else. That's to ensure no parasitic frequencies disturb the oscillator. That's what you get when you work with higher frequencies.

published 11 years ago