| Abstract: | A New Approach Has Been Presented To Find Characteristic Functions Of A Certain Class Of Monotonic Low-Pass Filters Of Non-Maximally Flat Type. The Well-Known Legendre Filters, And The More Recently Introduced Class H Filters, Both Belonging To This Class, Are Derived As Special Cases Of The Application Of Least-Squares Approximation Technique By Optimizing The Asymptotic Loss. It Is Shown That Class H Filters Provide Higher Stopband Attenuation Than The Legendre Filters But Have Less Favourable Passband Magnitude Response. On The Other Hand, If The Minimization Of The Passband Loss Is At A Premium Then The Unconstrained Least-Squares Monotonic Approximants, Referred To As Lsm Filters, Yield The Best Results. Therefore, Among All Filters With Monotonic Magnitude Response, The Legendre Filters Have Neither Optimum Passband, Nor Optimum Stopband Performance, Though They Are Suitable For Some Applications. |
