| 摘要 |
A bulk acoustic wave delay line including a body of acoustic wave supporting material and having at least one planar surface capable of reversably converting longitudinal wave mode acoustic energy to shear wave mode acoustic energy, the delay line also including at least one transducer for converting electromagnetic wave energy to acoustic wave energy and vice versa for propagating said acoustic wave energy along a path, a major portion of which supports shear wave mode energy and which path is at least partially defined by the mode converting planar surface, the planar surface being treated to increase the attenuation of propagating acoustic wave energy thereat by a predetermined amount, the attenuation provided at said planar surface being relatively frequency independent as compared to the attenuation per unit time of the propagating acoustic wave energy in the delay line body whereby triple transit signal suppression is significantly increased while still maintaining a relatively wide band frequency response.
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