| 摘要 |
An array of transducer segments is arranged in columns, each of which has a multiplicity of segments. The segments are wired to permit excitation by one or the other of two opposite phases of high-frequency signal, and groups of segments can be excited with the same phase to approximate the shape of an annular-ring phase-reversal zone plate. By changing the groupings of the elements that are similarly excited, the position of the focal region produced by the zone plate is translated in lateral position. A ferrite-core transformer is conveniently employed for both phase splitting and addition of the echo signals received by the device.
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