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1. 发明专利

DE3670743D1 未知
公开(公告)号：DE3670743D1
公开(公告)日：1990-05-31
申请号：DE3670743
申请日：1986-08-05
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： HIRAI MASATO , KURATA MASAMI , YOSHINO RYOZO
IPC分类号： H04L12/42 , H04L12/28

2. 发明专利

JPH08298687A RADIO COMMUNICATION SYSTEM AND MOBILE RADIO TERMINAL 失效
公开(公告)号：JPH08298687A
公开(公告)日：1996-11-12
申请号：JP10192395
申请日：1995-04-26
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： SHIDA MASAAKI , ISHIDO TOMOAKI , HIRAI MASATO , SHIGESA HIDEHIKO , AOYAMA KOJI
IPC分类号： H04W24/02 , H04B1/713 , H04L12/28 , H04W84/20 , H04Q7/38
摘要： PURPOSE: To obtain a frequency hopping mobile communication system capable of automatically functioning a mobile radio station as a base station in accordance with a peripheral condition and automatically reconstituting a communication network. CONSTITUTION: The system consists of base stations 1a, 1b, 2a for generating control frames and radio communication terminals 3a to 3d for hopping frequency in accordance with the control frames. Each radio communication terminal executes the switching operation of a base station to be followed based upon the receiving state of a control frame and relation between the received control frame and the state of the terminal itself, judges which mode, a base station mode or a slave station mode, is to be selected to drive the terminal itself and executes the formation and reconstitution of a cell.

3. 发明专利

JPH04192646A DUPLICATE RING SYSTEM 失效
公开(公告)号：JPH04192646A
公开(公告)日：1992-07-10
申请号：JP31781790
申请日：1990-11-26
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： KURATA MASAMI , HIRAI MASATO
IPC分类号： H04L12/42
摘要： PURPOSE:To prevent system-down by devising the system such that a reproduction repeater delivers a fault to subordinate nodes without implementing loopback or bypassing on the occurrence of a fault such as power failure so as to allow a ring configuration controller to detect the fault surely when the reproduction repeater and the ring configuration controller are in existence in mixture in the system. CONSTITUTION:Stations ST are connected to transmission lines 2 in duplicate by a line concentrator 1 and connected in a ring by using a ring configuration controller 3 checking the normality of a data to configure the ring, and a reproduction repeater 4 to extend the length of the ring. The reproduction repeater 4 does not implement loopback and bypassing on the occurrence of a fault such as a power failure but allows subordinate devices to detect the fault. Since the ring configuration controller 3 recognizes the fault and eliminate a fault location from the ring through loopback, system-down is prevented, the ring is managed and the fault location is easily found out.

4. 发明专利

JPH01170106A DIFFERENTIAL AMPLIFIER CIRCUIT 失效
公开(公告)号：JPH01170106A
公开(公告)日：1989-07-05
申请号：JP32708487
申请日：1987-12-25
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： HIRAI MASATO , KURATA MASAMI
IPC分类号： H03F3/45
摘要： PURPOSE:To obtain a differential amplifier circuit in which the balance of both outputs of differential outputs are good by packing circuit elements connecting between the emitters of a pair of transistors to an object physically to the emitters of a pair of the transistors. CONSTITUTION:By connecting between the emitters of a pair of transistors Q1 and Q2 to compose the differential amplifier circuit by means of circuit elements (an R1, an R2 and a C), an amplification degree is controlled. At such a time, the circuit elements (the R1, R2 and C) are packed to the object physically to the emitters of the transistors Q1 and Q2. Then, the floating capacity to a ground to accompany the packing of the circuit elements (the R1, R2 and C) is attached to the object to both emitters. The ground impedances of both emitters are also made equal, and the balance of the impedances between both emitters are made good. Thus, the differential amplifier circuit can be obtained in which the balance of both outputs of the differential outputs are good.

5. 发明专利

JPS6243236A RELAY CONNECTION SYSTEM 失效
公开(公告)号：JPS6243236A
公开(公告)日：1987-02-25
申请号：JP18180785
申请日：1985-08-21
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： HIRAI MASATO , KURATA MASAMI , YOSHINO RYOZO
IPC分类号： H04L12/42
摘要： PURPOSE:To offset the crosstalk produced by a relay circuit with no attachment of an external parts by a relay connection system in a trunk coupling unit of a token ring. CONSTITUTION:The signal A sent from a transmission part 5 of a station 1-1 is transmitted to a reception part 4 of a station 1-2 through relays 5 and 8. While the signal B sent from a transmission part 5 of the station 1-2 is transmitted to the reception part 4 of a station 1-3 through relays 7 and 9. Here the positive side crosstalk C(+) of the signal B is produced to a terminal (c) from a terminal (b) of both relays 6 and 7 respectively. While the negative side crosstalk C(-) of the signal B is produced to a terminal (c) from a terminal (b) of both relays 8 and 9 respectively. Then both crosstalks C(+) and C(-) are added together between relays 6 and 9 as well as relays 7 and 8 through connections 14 and 15 and offset with each other. Thus no crosstalk C of the signal B is produced at the reception part 4 of the station 1-2.

6. 发明专利

JPH05199107A PHASE CONTROL SYSTEM FOR SYSTEM CLOCK 失效
公开(公告)号：JPH05199107A
公开(公告)日：1993-08-06
申请号：JP675192
申请日：1992-01-17
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： NAKAUCHI TOSHIHIKO , HIRAI MASATO , KURATA MASAMI
IPC分类号： H03L7/00 , G06F1/04 , H03K5/00 , H03L7/08 , H03L7/14 , H04L7/033
摘要： PURPOSE:To attain quick phase synchronization by implementing phase control at the interruption or recovery of a system clock used to synchronize a public digital network and the entire nodes in a LAN. CONSTITUTION:A PLL comprising a phase comparator 21, an LPF 22, a VCO 23 and a frequency divider is synchronized with an external clock 38 and a system clock 53 is formed in this system, and the system is provided with an internal clock oscillation source 30 used to supply the clock whose clock deviation is warranted at the interruption of the external clock. The system is provided with a system clock phase control circuit 56 which controls the phase of the system clock 53 when the system clock 53 is replaced with the internal clock from a PLL output clock or with the PLL output clock from the internal clock. Thus, a phase step caused at the system clock changeover at the interruption or recovery of the external clock is relaxed.

7. 发明专利

JPH0432330A SYSTEM CLOCK PROTECTION SYSTEM 失效
公开(公告)号：JPH0432330A
公开(公告)日：1992-02-04
申请号：JP13702690
申请日：1990-05-29
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： HIRAI MASATO , KURATA MASAMI , NAKAUCHI TOSHIHIKO
IPC分类号： H04L7/033 , G06F1/08 , H03L7/14
摘要： PURPOSE:To hold the frequency and phase constant by switching an input to a frequency divider in a phase locked loop into a reference clock provided on the inside of the system at the time of the interruption of an external clock. CONSTITUTION:When a clock 25 from an external network is lost, an interruption detection circuit 35 detects the state and generates a switching signal 36 and a selector 33 selects an input to a frequency divider 24 from the output 27 of a VCO 23 into the output of a reference oscillator 34. Since the frequency of the reference oscillator 34 is within a permissible deviation, the internal clock 26 of the output of the frequency divider is hold within a prescribed frequency range. Moreover, although the phase fluctuation of a maximum of 180 deg. takes place in the input phase to the frequency divider 24 by the switching, since the phase fluctuation of the internal clock 26 being the output of the frequency divider 24 is decreased to 1/N, when the N is larger, the internal clock is selected almost without phase fluctuation. Thus, not only the frequency but also the phase is held constant.

8. 发明专利

JPH03226052A FAULT DETECTION SYSTEM 失效
公开(公告)号：JPH03226052A
公开(公告)日：1991-10-07
申请号：JP1881790
申请日：1990-01-31
申请人： HITACHI LTD , HITACHI COMPUTER ENG
发明人： KURATA MASAMI , HIRAI MASATO
IPC分类号： H04L29/14 , H04L12/42
摘要： PURPOSE:To easily grasp a fault state of a transmission line by switching a level of a reception signal inputted to a receiver, decreasing the level of the reception signal inputted to the receiver and generating a data fault solidly caused only intermittently. CONSTITUTION:An attenuator 9 is inserted when a data fault is detected and removed basically when the data fault is lost but the removal is controlled so that the attenuator is removed at a prescribed time after the data fault is lost by taking intermittent production of the data fault into account. When one broken transmission line 8 takes place, a data fault is caused sometimes and its reception level reaches L2-L3, the attenuator 9 is inserted to the circuit to bring the succeeding reception level to be L2 or below in which the data fault is caused solidly and the transmission line fault is easily detected.

9. 发明专利

DE3926091C2 未知
公开(公告)号：DE3926091C2
公开(公告)日：1997-09-04
申请号：DE3926091
申请日：1989-08-07
申请人： HITACHI LTD , HITACHI COMPUTER ELECTRONIC
发明人： HIRAI MASATO , BEKKI YOSHINORI , IKEZAWA SINZI , MORIGUCHI TERUO
IPC分类号： H04L12/437 , H04L25/24 , H04L29/14 , H04L12/28 , H04L25/08
摘要： A regenerative repeater for regeneratively repeating a signal to be transmitted is inserted in two ring-like transmission lines, and is provided with loop back means for automatically separating the regenerative repeater from the ring-like transmission lines in the condition that a power supply is in a not-yet-turned-on state, so that closed ring-like transmission lines are formed in the form where the regenerative repeater is removed in the condition that the power supply is in the not-yet-turned-on state.

10. 发明专利

DE3926091A1 未知
公开(公告)号：DE3926091A1
公开(公告)日：1990-03-15
申请号：DE3926091
申请日：1989-08-07
申请人： HITACHI LTD , HITACHI COMPUTER ELECTRONIC
发明人： HIRAI MASATO , BEKKI YOSHINORI , IKEZAWA SINZI , MORIGUCHI TERUO
IPC分类号： H04L12/437 , H04L25/24
摘要： A regenerative repeater for regeneratively repeating a signal to be transmitted is inserted in two ring-like transmission lines, and is provided with loop back means for automatically separating the regenerative repeater from the ring-like transmission lines in the condition that a power supply is in a not-yet-turned-on state, so that closed ring-like transmission lines are formed in the form where the regenerative repeater is removed in the condition that the power supply is in the not-yet-turned-on state.

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