I have this ordinary Sallen Key bandpass filter: -
I'm being asked, if the system is linear and/or time-invariant and/or causal. Furthermore, if the decomposition property holds for this system.
The system is linear, because the superposition principle holds.
The system is time-invariant, because a time-shifted input yields a correspondingly time-shifted output.
The system is causal, because the output depends only on present and past inputs.
The decomposition property is based on the principle of superposition. Since superposition holds, the system has the decomposition property.
As you can see, my answers doesn't have much argumentation, and I'm not 100% sure if what I've written is correct. Is there a reliable way to check if these properties, for example through simulation?