A Nomogram for the Band Pass Filter (Zobel Type)

A direct and very important method of designing band pass filters has been given by Zobel, ¿ who finds that there are eight types of filter sections of special importance. In a later paper¿ Zobel gives methods for computing the attenuation of these sections: but these methods are fairly lengthy and it is very inconvenient to apply them to the various types of sections that are tried before a final design is achieved. This paper gives a method for calculating the attenuation of the eight types of sections by means of a nomogram, so that the preliminary calculations can be made very quickly and easily and then the detailed calculation of Zobel can be applied to the final structure. The method employed simplifies the problem of design considerably.