Magnetostrictive delay line

Tabulates a qualitative comparison of (1) wound delay lines, (2) liquid and solid supersonic, (3) delay multivibrator and phantastron, (4) pulse-excited and resonant circuit, and (5) magnetostrictive metal ribbon types. In type (5) a sound-conducting and magnetostrictive ribbon such as nickel is threaded through a transmitting and receiving transducer. A pulse in the former is transmitted as a sound wave in the material along which it travels to excite the receiving transducer. The time delay is given by t = L/(E/p)frac12 where L = length between transducers, E = Young's modulus and rho = density of material. For a pure nickel ribbon t = 5middot27musec/in. A practical delay line of this type is described in detail with photos, diagrams of pulse shapes and method of constructing the transducer coils. Since the wave is launched from each end of the transducer in opposite directions reflections occur. Methods of suppressing echoes are discussed.