摘要 |
A variable delay line for surface acoustic waves includes spaced input and output transducers affixed on the wave-propagating surface of a piezoelectric substrate for sending and receiving acoustic waves. An AC or DC voltage is applied to the substrate through a pair of electrodes as a strain inducing signal. The applied voltage changes the time delay of the wave by physically altering the length of the propagation path, and/or by altering the effective properties of the substrate to vary the propagation velocity of the wave. The time delay will vary proportionately in response to the applied voltage.
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