| 摘要 |
PURPOSE:To select the amount of delay at <=2pi, phase pitch by constituting a titled delay element that the ratio of the electrode width to the electrode pitch of at least one of input/output transducers is decreased and the transducer is shifted once or over in parallel with the propagating direction by a distance smaller than one wavelength of a surface acoustic wave. CONSTITUTION:A width (d) of each electrode is lambda/10 and a pitch (s) of each electrode is lambda/10 also. The distance between the electrodes 5N and 5N+5 is lambda/2 and an electric signal is extracted in the same manner as for a conventional comb line transducer. The distance between 5N+1 and 5N+6 being another electrode pair is also lambda/2 and the electric signal is extracted. The electrode pair 5N, 5N+5 and the other electrode pair 5N+1, 5N+6 are shifted by lambda/10 as a whole, and there is 2pi/10 phase delay difference in output signals obtained from them. Thus, the amount of delay is selected by 2pi/10 pitch by selecting an arbitrary electrode pair. |
