A Single-Sideband, Disk-Wire Type Mechanical Filter

A mechanical filter with real frequency transmission zeros on the high-frequency side of the passband has been developed. These points of infinite attenuation are produced through the coupling of alternate disk resonators by short lengths of wire. A procedure for designing this type of filter through use of electrical analogies is discussed in some detail. The amplitude and envelope delay characteristics of a presently manufactured 100 kc/s, single-sideband (SSB) filter being used in broadband carrier systems are described. This filter is one of a set of twelve SSB filters having carrier frequencies ranging from 64 kc/s to 108 kc/s. The use of finite frequency transmission zeros has made possible a 30 per cent reduction in differential delay over conventional constant-K models.