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1. 发明专利

JPH05308242A 失效
公开(公告)号：JPH05308242A
公开(公告)日：1993-11-19
申请号：JP10951092
申请日：1992-04-28
申请人： HITACHI LTD
发明人： HIKITA MITSUTAKA , TABUCHI TOYOJI , OKAZAKI KATSUNORI
IPC分类号： H03H9/02 , H03H9/145 , H03H9/64
摘要： PURPOSE:To realize a surface acoustic wave(SAW) filter with low loss or a filter covering a wide band by employing an electrode finger whose width is a minimum of 1/16 of the wavelength of the SAW. CONSTITUTION:An exciting electrode finger 6-1 whose width is lambda0/8 with respect to the wavelength of a SAW is provided to a region L symmetrically in the horizontal direction and earth electrode fingers 7-1, 8-1 whose width is lambda0/16 are in existence at both sides via a space of lambda0/8. Through the constitution above, since electric force of lines are in existence symmetrically in the horizontal direction in the region L, it is possible to excite SAWs of the same amplitude and phase in the horizontal direction. Then earth electrode fingers 7-1, 8-1 whose width is lambda0/4 are arranged to the left at the outside of the region L and a space of lambda0/4 is arranged to the right. That is, the SAW excited in the region L is propagated toward the outside of the region L, but the propagation condition differs in the right and left directions. The different propagation region is in existence at both sides of the SAW excitation region whose width is L and a periodic structure is adopted for the entire transducer as one SAW.

2. 发明专利

JPH11112467A RF SIGNAL PROCESSOR FOR CDMA COMMUNICATION USING SAW 失效
公开(公告)号：JPH11112467A
公开(公告)日：1999-04-23
申请号：JP27079897
申请日：1997-10-03
申请人： HITACHI LTD
发明人： HIKITA MITSUTAKA , TAKUBO CHISAKI , ASAI KENGO , SHIBAGAKI NOBUHIKO , OKAZAKI KATSUNORI
IPC分类号： H03H9/42 , H03H9/72 , H04B1/707 , H04B1/708 , H04B1/7093 , H04J13/00
摘要： PROBLEM TO BE SOLVED: To demodulate the spread spectrum signal of high efficiency without requiring a generation circuit, or the like of a replica signal by inputting two high frequency signals to two surface acoustic wave(SAW) delay element, mixing respective output signal by a mixer and taking out the output signal of the frequency of difference. SOLUTION: Concerning a first delay element, a transducer 15 for SAW excitation and transducers 16-1 to 16-N for reception are formed at a piezoelectric substrate 1. Concerning a second delay element, a transducer 18 for SAW excitation and transducers 19-1 to 19-N for reception are formed at a piezoelectric substrate 1. The spread spectrum signal of a frequency fRF is inputted from a first input terminals 14. The nonmodulation continuous waves of a frequency fLO is inputted from a second input terminals 17. Each output signal from each delay element is mixed by mixers 20-1 to 20-N to obtain the output signals O(1) to O(N) of the frequency |fRF-fLO|of difference.

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