How to implement a low pass and a band pass filter?

I would like to implement a 2nd order low pass filter with a cut off frequency of 10 rad/s. I would also like to implement a 2nd order bandpass filter with a passband of 10 rad/s to 20 rad/s. I would like both of these to be second-order so that the roll-off is faster relative to the first order.

How can I implement this in MATLAB for a signal sampled at 0.001 s?

Answer 1

[MathWorks Support Team]

The filter order used while implementing the filter is very low for the very stringent frequency specifications. The filter is designed with a cutoff frequency of 0.47 and a sample rate of 1000 Hz.

Both the lowpass and bandpass designs are completely off because of the 10 order FIR filter as it is not large enough for the very small cutoff frequencies.

The correct way to solve this filtering problem is to resample the signal to a much lower sample rate and to design the filters with less stringent specifications. If this is not possible, then it will be helpful to use a much higher filter order or consider an IIR design