A unified analysis of ultrasonic delay lines is presented with particular attention paid to the characteristics of direct‐current pulse transmission. The analysis can be applied to any delay line, whether piezoelectric or magnetostrictive, regardless of whether the mode of transmission is longitudinal, shear, or torsional, as long as the motion is adequately described by the one‐dimensional theory on which the equivalent circuits are based.
Characteristics in the time domain are obtained in terms of the time‐shift operators of Laplace transform calculus. This makes it possible to easily obtain the output waveform for any arbitrary input. Three transducer configurations are discussed; namely, a line with transducers in the middle of the delay medium (Case A), a line with one of the transducers at the free end of the delay medium (Case B) and a line with transducers at both free ends of the delay medium (Case C).
The latter two configurations are especially useful for a delay line made of a ferrite or piezoelectric ceramic, both of which are available in limited length only due to manufacturing difficulties. Cascading of several pieces of material in order to obtain a longer delay than that which is available using a single piece is discussed. The effects of acoustic mismatching at bonding points on the signal‐to‐noise ratio and on the ringing in the output are presented.