To obtain the frequency response of a circuit, or its Bode plot, using LTspice, it helps to start with a simple circuit example. Figure 1 shows a second-order low-pass filter. The input and output ...

Redraw the circuit as here in Figure 1 with the definition of the voltage β. Figure 1: Op amp as a gain stage (Click on image to enlarge) Treating the gain setting resistors as a voltage divider ...

Some calculations on the result reveal how much of the signal is attenuated and its phase, resulting in a Bode plot. The filtering is done through digital signal processing from a microcontroller.

My circuit was a simple Colpitts oscillator and the simulation showed that it would indeed oscillate. However, I wanted to look at the transfer function of the passive components just to make sure ...