| 摘要 |
PROBLEM TO BE SOLVED: To suppress a timewisely shifted convolution peak in an output signal by allowing the unnecessary surface acoustic wave excited from an arcuate comb-shaped electrode to reflect on the end face but not to input to the output electrode. SOLUTION: When a signal having a carrier angular frequency ω is inputted to arcuate comb-shaped input electrodes 12, surface acoustic waves are excited by the piezoelectric effect of a piezoelectric substrate 11, and an output electrode 13 becomes a Δ V/V waveguide and they are propagated on the substrate 11 in opposite directions while being confined in this waveguide. Two waves strike on the electrode 13, abd a convolution signal having a frequency 2ω is taken out from the electrode 13 by the nonlinear effect of the substrate. At this time, two electrodes 12 are provided in such form that surface acoustic waves are concentrated to the electrode 13; and thereby, surface acoustic waves propagated in the direction opposite to the electrode 13, namely, waves propagated to both end faces 14 of the substrate 11 become unnecessary waves, and timewisely shifted signals are not inputted to the electrode 13, and thus, a timewisely shifted comvolution peak doesn't appear in the output signal. |
