For a Multiple-Feedback (MFB) active filter, what do component values primarily determine?

For a Multiple-Feedback (MFB) active filter, what do component values primarily determine?

• A. Only center frequency.
• B. Quality factor (Q) and center frequency.
• C. Only gain.
• D. Noise performance.

Answer: (B)

In a multiple-feedback active filter, the passive network around the op-amp sets the locations of the poles of the transfer function. Those pole locations determine the center frequency and how sharply the filter responds, i.e., the Q factor. So choosing the resistor and capacitor values primarily tunes where the center frequency lies and how selective the filter is. The overall gain at the center frequency comes mainly from the amplifier configuration and feedback resistor ratios, not from the pole positions themselves. Noise performance, while influenced by resistor values and the op-amp, is not what these component choices primarily establish.

In a multiple-feedback active filter, the passive network around the op-amp sets the locations of the poles of the transfer function. Those pole locations determine the center frequency and how sharply the filter responds, i.e., the Q factor. So choosing the resistor and capacitor values primarily tunes where the center frequency lies and how selective the filter is. The overall gain at the center frequency comes mainly from the amplifier configuration and feedback resistor ratios, not from the pole positions themselves. Noise performance, while influenced by resistor values and the op-amp, is not what these component choices primarily establish.