| 摘要 |
PURPOSE:To attain a small-sized circuit and to reduce the cost by using a surface acoustic wave device provided with 1st - 3rd interdigital electrodes so as to form a distribution delay circuit and specifying the arrangement of each interdigital electrode. CONSTITUTION:The distribution delay circuit 11 is formed by using the surface acoustic wave device(SAW) device 11. The SAW device 11 has the 1st interdigital electrode(IDT) 101 being an input terminal and 2nd and 3rd IDT 102, 103 being output terminals. Then the IDTs 101, 103 are arranged so that the signal propagated between the 1st IDT 101 and the 2nd IDT 102 and between the 1st IDT 101 and the 3rd IDT 103 is subject to a delay corresponding to one bit of each data signal respectively and also phase delay of + or -(2n-1)pi/4 (where n=1, 2, 3, 4...). Thus, the demodulation circuit small in size and low in cost is obtained. |
