Butterworth filter has Select one:Ripple in STOP  BandRipple in PASS BandRipple in PASS Band and STOP BandNO Ripple in PASS Band and STOP Band

The Butterworth filter is known for its flat frequency response in the passband and has no ripples, meaning it is designed to have a maximally flat magnitude response.

Explanation of Options:

1. Ripple in STOP Band: This option is incorrect because the Butterworth filter is designed to have a monotonic roll-off in the stop band without any ripples.

2. Ripple in PASS Band: This option is also incorrect, as the Butterworth filter is characterized by its smooth and flat response in the pass band.

3. Ripple in PASS Band and STOP Band: This option is incorrect since the Butterworth filter is specifically designed to avoid ripples in both bands.

4. NO Ripple in PASS Band and STOP Band: This is the correct answer, as the Butterworth filter features a flat frequency response with no ripples in both the pass band and stop band.

Final Answer:

NO Ripple in PASS Band and STOP Band