Adjacent channel rejection by magneto-striction (US Patent 2599068)

Application October 31, 1950, serial No 193080, patented June 3, 1952. 5 p.This invention relates fo interstage coupling transformers for use in signal amplifying systems. More particularly this invention relates to fixed frequency coupling transformer utilizing electromechanical elements to achieve a highly selective bandpass network suitable for use in selective signal amplifying systems such as intermediate-frequency amplifiers.Magnestostrictive effects have been observed by investigators for the past 50 years or more. One of the effects noted is the decrease in the electrical impedance of an inductor or coil over a very narrow band of frequencies when associated with a polarized vibrating element of magneto-strictive material having a predetermined frequency of its mechanical resonance.