I designed a sine wave oscillator, but the frequency isn't correct and the wave shape is weird. I use 5V single supply. I create a 2V common point to be virtual ground. The opamp is acting as a non-inverting amplifier. There is a feedback diode in parallel to control the amplitude. The LC in series should act as a bandpass filter to select the frequency. What's wrong with the circuit?
I built the circuit in practice, and the result is almost the same as the simulation result.
I think, the design of the negative feedback path is not good. At the series resonance of the LC-bandpass the positive feedback is app. 50%. At the desired oscillation frequency, the negative feedback factor should be slightly smaller.
But why you have chosen (for small amplitudes) a negative factor as small as k(-)=22/69=0.32 ? I would propose to split the feedback R2 resistor in two parts:
20k plus 3k (with antiparallel diodes across 3k only). This ensures a "good" soft-limiting for the amplitudes.
The circuit operates at two different gains, one when the voltage across R2 is less than 0.6 V in either direction, and one when that voltage tries to be greater than 0.6 V and the diodes conduct.
To soften the transition between these two gain values, add a resistor in series with the diodes, between the right-side ends of the diodes and the opamp output.
