My circuit works well only with a small output signal. I do not understand why you put (use) an attenuator. You can also change the transmission factor for a triangular signal.

 

My circuit works well only with a small output signal. I do not understand why you put (use) an attenuator. You can also change the transmission factor for a triangular signal.

Because i want to use the resistor divider to generate the +-0.6mV and in LTspice it works well. But in the experiment it didn't work and generate a strange wave. I don't know why.
So i have to change the value of the resistor divider to generate bigger amplitude as yours +-50mV and the problem solved. Now i want to change the frequency from 2MHz to 1MHz, and the waveform is with curve.
I will try to change the value of the resistor divider one more time to generate smaller amplitude in the experiment. In LTspice it works, i am not sure in the experiment.
You have mentioned i have put (used) an attenuator. You mean which one? And what is the reason that this circuit can generate smaller amplitude well and bigger badly.

Thanks
Jackie