| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a demodulation circuit and to reduce cost by forming an input electrode on the surface of a piezoelectric substrate, encoding a first output electrode in accordance with an N code series and relatively arranging a second electrode backward to the first output electrode being viewed from the input electrode by the series length of a PN code series. SOLUTION: An input electrode 3, a first output electrode encoded accordance with a PN code series for spread spectrum, namely, a whole stage output electrode and a second output electrode 5 which is encoded in accordance with the PN code series and in which whole electrodes are relatively arranged backward to the whole stage output electrode 4 by the series length of a PN series being viewed from the input electrode 3, namely, a post-stage output electrode, are arranged in series on a piezoelectric substrate 2. Thus, a prestage electrode output signal 6 and a poststage electrode output signal 7 are used as they are and a delay detection circuit is constituted by arranging the two independent output electrodes 4 and 5 on the piezoelectric substrate 2 so that a spread spectrum signal and the correlation value of a matching filter can be obtained over two continuous symbols. |
