Functional Circuits Through Acoustic Devices

In essence, the communication specialist in the field with his complex electronic gear and the native who beats a hollow log both perform the same function-communication over a distance. However, there is no gainsaying that the hollow log is undoubtedly the more reliable of the two communication equipments. The implication of this analogy is not as far fetched as it may appear. It has been found that considerable circuit simplification with a consequent increased reliability are attainable through the application to electronic circuits of the mechanical and acoustic properties of certain materials. Miniaturized, rugged, low cost, highly selective band-pass filters ranging from 100 cps to approximately 10 Mc are feasible. Power transformers without core or coil are definite possibilities. Stable delay media provide large delays in small simple packages. Hybrid structures of conventional parts and nonconventional resonators provide techniques for broadbanding and impedance transformation. A new element, it is expected, will soon be generated for use at low frequencies-a passive four-terminal nonreciprocal network.