Why does the implementation of a buffer amplifier separating the high-pass and low-pass filter of a bandpass filter affect the transfer function of the bandpass filter?
I thought the point of a buffer amp was to keep the output voltage equal to the input voltage regardless of current draw at the output. Therefore I would expect there to be no change assuming no current is being drawn at the input or the output and all components are ideal.
Unfortunately it seems the transfer function of both filters and their behaviour is different and I don't know why.
- Buffer amplifier present:
- Buffer amplifier not present: