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2. 发明专利

JPS6320066B2 失效
公开(公告)号：JPS6320066B2
公开(公告)日：1988-04-26
申请号：JP2499179
申请日：1979-03-02
申请人： FUJITSU KK , NIPPON DENSHIN DENWA KK , NIPPON DENKI KK
发明人： SAKAI TAKESHI , SHIMADA MASAHARU , KATO YOSHIBUMI
IPC分类号： H03M5/16 , G06F3/00 , H04L7/02 , H04L7/04 , H04L25/38 , H04L25/40 , H04L25/49

8. 发明专利

JPH034148B2 失效
公开(公告)号：JPH034148B2
公开(公告)日：1991-01-22
申请号：JP5947384
申请日：1984-03-29
申请人： NIPPON DENSHIN DENWA KK , NIPPON DENKI KK
发明人： SHIMADA MASAHARU , YASUKAWA HIROSHI , FURUKAWA ISAO , KIJIMA RYOJI , ITO YASUO
IPC分类号： H04M3/56

10. 发明专利

JPH0155425B2 失效
公开(公告)号：JPH0155425B2
公开(公告)日：1989-11-24
申请号：JP21408081
申请日：1981-12-24
申请人： NIPPON DENKI KK , NIPPON DENSHIN DENWA KK
发明人： KOYAMA TOORU , KOMYA HISHIICHI , SHIMADA MASAHARU , SASAGAWA MASAAKI
IPC分类号： G01R31/02
摘要： PURPOSE:To detect easily a fault such as the disconnection, short circuit, etc. of a paired cables, by connecting an oscillating circuit and a low pass filter to an end of a pair of cables and then a rectifying circuit to the other end of the paired cables to rectify the signal given from an oscillator. CONSTITUTION:A low pass filter consists of an oscillator 31, an accumulator 27, a resistor 30, etc. is connected to an end of a pair of cables 16. At the same time, a rectifying circuit consists of an impedance varying circuit 23, a diode 24, etc. is connected to the other end of the cable 16 to rectify the signal supplied from the oscillator 31. If there is no fault on a line, a signal having a DC component is detected at the output of the low pass filter by the function of the rectifying circuit. In case a line fault arises, the signal having a DC component is not detected at the output of the low pass filter since the rectifying function of the rectifying circuit does not emerge at a measuring terminal. In such a way, a fault like the disconnection, short circuit, etc. can be easily detected for paired cables with a simple constitution of circuit.

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