For any newcomer looking for reference material on this topic, look at https://ccrma.stanford.edu/~jos/filters/ https://ccrma.stanford.edu/~jos/filters/ and his

For any newcomer looking for reference material on this topic, look at https://ccrma.stanford.edu/~jos/filters/ https://ccrma.stanford.edu/~jos/filters/ and his other books which are quite thorough.