A special case of the Achieser-Zolotarev filter

Achieser-Zolotarev filters are similar to the familiar Chebysbev filters except that the first ripple (DC end for low pass, HF end for high pass) is larger than the others, limiting the use of these filters to applications where only the upper part (low pass), (lower part, high pass), of the passband will be used. The advantages of these filters are a slightly increased attenuation in the stopband and the ability to choose the impedance level within the filter. [1] In this letter it is pointed out that the impedance level may be chosen to produce filters with all even numbered elements equal in value giving a simpler filter. Tables for design of these filters are provided.