| 摘要 |
PROBLEM TO BE SOLVED: To provide the surface acoustic wave convolver with a characteristic where a signal level difference is small in the interior of an operating band width and a ripple is small by executing weighting only to teeth close to a focus of interdigital electrodes and to teeth remote from the focus. SOLUTION: The surface acoustic wave convolver is provided with a convolution output electrode 2 on a piezoelectric substrate 1 and comb-like electrodes 3 are arranged on both sides. The comb-like electrode 3 has lots of teeth 5, which are made up of a couple of positive and negative teeth and they are arranged at a prescribed interval in a surface wave propagation direction of A. The teeth 5 are formed on a circular-arc face around a focus 4. The length of each tooth 5 is selected gradually to be longer so as to be set within a range of a circular-arc angleα. The proper number of the teeth 5 closest to the convolution output electrode 2 and of the teeth 5 remotest from the electrode 2 is weighted according to a window function. In this case, a maximum value and a minimum value of ripples are small, the characteristic is made smooth at both sides of the operating band width and an undesired signal is considerably reduced at the outside of the band.
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