I have attached the circuit file in the comments, dear sir. I have a question.
1) I generated two signals: one is 2 V peak (Vp) and the second is 2.5 V peak (Vp), with frequencies of 5 MHz and 6 MHz, respectively. In the real circuit, if I don't use ferrite beads after the operational amplifier, both signals show a very high level of distortion. I managed to reduce the noise and distortion by using ferrite beads. However, in the LTSpice simulation, when I don't use ferrite beads and the low-pass filter (LPF), the signal amplitudes become very accurate. But when I use either the ferrite beads or the LPF (or both), there are fluctuations in the signal amplitude. For example, if I only consider the 2.5 Vp signal and check its amplitude throughout, in one cycle, the amplitude sometimes drops to 2.44 Vp, 2.48 Vp, or 2.49 Vp. How can I achieve a constant amplitude of 2.5 Vp? Why does adding the LPF and ferrite beads in the simulation cause amplitude fluctuations, whereas in reality, they improve the signal's distortion and noise levels?
2) When I use the LPF before the operational amplifier, there is a slight drop in signal amplitude, but I understand this is a common occurrence. Could you please check my circuit and suggest any improvements or modifications?