As one of the interesting problems in the fields of physics and electronic engineering, the interaction between electron and elastic waves in solids is generally surveyed. Though phonon-electron interaction and phonon-magnon interaction are really understood as quantum interactions, many phenomena of the interactions are preferably treated with such macroscopic methods as those for the travelling-wave amplification in semi-conductors. The author proposes a new word "acousto-electronics" as the name of this field of learning whitch covers all kinds of interactions between electron and elastic waves in solids, regardless of their theoretical treatments, quantum mechanical one or macroscopical one basing on a phenomenological standpoint. Among the descriptions of the general survey, (i) a new amplifier device of CdS crystal with integrated diffusion-layer transducer and a co-planar construction of the diffusion-layer transducer are briefly explained as the author's proposal for engineering use; (ii) the extinguishing devices for the so-called anomallous oscillation in the travelling-wave amplifier devices are described, which are recentry proposed in Japan; (iii) the noise figure of travelling-wave amplifier is discussed with the author's opinion that the improvement of transducer efficiency directly results in the improvement of the noise figure though difficult because its frequency band should be kept wide enough; and (iv) as a potential engineering interest, the travelling-wave amplification with the use of deformation potential is pointed out, designating this a "large-current small-coupling type" in contrast to the "small-current large coupling type" as of the amplification with the use of piezo-electricity of semiconductors.
