| 摘要 |
PURPOSE:To obtain electrically a delay signal being variable continuously by arranging a semiconductor element extracting an output of a convolution phenomenon of an elastic surface wave and inputting an object signal whose delay time is desired to be changed continuously to a reed screen electrode so as to eliminate ripple produced due to multiplex reflection between electrodes. CONSTITUTION:A lithium niobate single crystal of 128 deg. rotation Y axis cut is used as a piezoelectric substrate 1 and the direction of propagation of an elastic surface wave is taken as the X axis. The center frequency of one input reed screen electrode 8 is 60MHz and the number of pairs of the electrode is 20. The center frequency of the other electrode 9 is 60MHz and the number of pairs of the electrode is 1.5 with broad band characteristic. Any of the electrodes is of double electrode structure and aluminum vapordeposition film in 6,000Angstrom is formed by the photo lithography method. Further, a silicon single crystal is provided on a spacer made of silicon oxide in 8,000Angstrom formed by sputtering in the semiconductor element 6 and an aluminum electrode is arranged on its upper part as an output electrode. As external circuits, a continuous variable delay pulse generating circuit 11 is provided to a broad band input terminal 5 and a demodulation circuit 10 is provided to an output terminal side. |
