Design an analog filter by experimenting with the s-plane poles and zeros of a transfer function. Remember, the poles of a causal filter must be strictly in the left half of the complex s-plane. You can also try pre-made Butterworth and Chebyshev low-pass filters.

Alternatively, design a digital filter by setting the z-plane poles and zeros of a transfer function. Remember, the poles of a causal filter must be strictly inside the unit circle in the complex z-plane.