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Home Electric Networks Filters mDerived Sections  


mDerived SectionsStructures known as mderived sections have good impedance characteristics and sharp cutoff frequencies. In Fig. 42 are shown T, or midseries, sections, and as explained in the preceding section mderived and constantk sections are used together to make composite filters. These mderived sections have attenuation characteristics shown in Fig. 43. It will be noted that both m and a are shown on these curves, the relation between these two quantities being as follows
where
In this relation f_{∞} is the frequency at which the attenuation of the mderived section reaches a theoretical value of infinity (Fig. 43), and f_{c} is the cutoff frequency of the constantk prototype, that is, the constantk section to which the mderived section is related by the factor m. Referring to Fig. 42, if m = 1.0, the derived sections become the constantk prototype.


Home Electric Networks Filters mDerived Sections 