Electromechanical filters for 50 to 500 kilohertz

Mechanical vibrators are first discussed generally and then the remainder of the paper deals with the properties of torsional vibrators. Electromechanical filters consisting of system of coupled resonators and equivalent to an electrical ladder network are described and equations given for determining an equivalent mechanical structure. Two basic types of transducer, piezoelectric and magnetostrictive, are described and the properties of the materials employed briefly considered. Design parameters are given for constant-k filters, Butterworth or maximally flat filters, Chebyshev filters, narrow-band and broad-band filters. The performance of a range of practical filters is described.