Communication Networks

THE latest developments of the filter question are now made available in English, together with the most useful parts of the more difficult classical treatments by Zobel. It will be recalled that, starting with Campbell, the properties of filter sections of specified patterns were tabulated for procedure in design, which, after all, is the important aspect for the communication engineer; the actual design along these lines was, however, an art, in that many tries were often necessary for a satisfactory solution to the problem. Starting again with Cauer, the procedure previously based on deductions from transmission line conceptions gave way to conceptions based on obtaining network structures having specified impedances, using a theorem by Foster and the most general of filter structures, the lattice. Guillemin's second volume is therefore of considerable practical importance. Transient phenomena in filters are adequately dealt with, together with Bode's methods of impedance control.Communication NetworksProf.Ernst A.Guillemin. Vol. 2: The Classical Theory of Long Lines, Filters and related Networks. Pp. vii + 587. (New York: John Wiley and Sons, Inc.; London: Chapman and Hall, Ltd., 1935.) 37s. 6d. net.