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1. 发明专利

JP2544404B2 失效
公开(公告)号：JP2544404B2
公开(公告)日：1996-10-16
申请号：JP25678687
申请日：1987-10-12
申请人： FUJITSU LTD
发明人： FUKUGAHARA TSUTOMU , ICHIKAWA AKIHIKO , SHIMIZU KAZUYOSHI
IPC分类号： H04B10/572 , H01S5/068 , H01S5/0683 , H04B10/00 , H04B10/07 , H04B10/293 , H04B10/524 , H04B10/564 , H01S3/133 , H04B10/04 , H04B10/06 , H04B10/14

2. 发明专利

JPH01318324A DISTORTION IMPROVING METHOD 失效
公开(公告)号：JPH01318324A
公开(公告)日：1989-12-22
申请号：JP15083388
申请日：1988-06-17
申请人： FUJITSU LTD
发明人： SHIMIZU KAZUYOSHI , FUKUGAHARA TSUTOMU , ICHIKAWA AKIHIKO
IPC分类号： H04B3/04
摘要： PURPOSE:To improve the distortion of an output signal of a distortion generating circuit by adding an oscillator and a synthesis means to the pre-stage of the distortion generating circuit. CONSTITUTION:An oscillator 600 outputs a signal with a prescribed frequency higher than the frequency of an input analog signal. Then the output of the oscillator 600 is inputted to a synthesis means 500 together with the analog signal to overlap the high frequency signal being the output of the oscillator 600 on the analog signal and the output of the synthesis means 500 is fed to the distortion generating circuit 300. Thus, the peak of the distortion generated in the distortion generating circuit 300 is averaged with other part and the distortion is reduced. Then the output of the distortion generating circuit 300 is given to a low pass filter which passes only an analog signal. Thus, the distortion in the output signal of the distortion generating circuit is improved.

3. 发明专利

JPH01255328A LIGHT INPUT DISCONNECTION DETECTING CIRCUIT 失效
公开(公告)号：JPH01255328A
公开(公告)日：1989-10-12
申请号：JP8274488
申请日：1988-04-04
申请人： FUJITSU LTD
发明人： FUKUGAHARA TSUTOMU , ICHIKAWA AKIHIKO , SHIMIZU KAZUYOSHI
IPC分类号： H04B10/07
摘要： PURPOSE:To surely detect a light input disconnection in a circuit not to have an automatic gain control(AGC) loop by providing a band blocking filter to have a prescribed center frequency between the input and output of a first amplifier. CONSTITUTION:A band blocking filter 250 to make a frequency higher than the frequency of an input light signal by the degree of a prescribed quantity into the center frequency is connected to the input and output of a first amplifier 200 in parallel, and a feedback is prescribed from being applied in the center frequency. As a result, at the time of a disconnecting the light input, the noise components of the center frequency are amplified, the amplitude of the noise is slice at a prescribed value by a limiter function which a second amplifier 300 has, and a pulse-shaped output can be obtained. Thus, the noise components to be small at the time of inputting a signal to the output of a band-pass filter 320 is made large at the time of disconnecting the input signal, and by detecting it, the light input disconnection can be surely detected in the circuit not to have the AGC loop.

4. 发明专利

JPS645486B2 失效
公开(公告)号：JPS645486B2
公开(公告)日：1989-01-31
申请号：JP16103179
申请日：1979-12-12
申请人： FUJITSU LTD
发明人： IGUCHI KAZUO , NAKAMURA HIROSHI , HANANO NAOMASA , FUKUGAHARA TSUTOMU , TAKAHASHI MASAAKI
IPC分类号： H03K5/1532 , G01R19/04 , H03D1/18 , H03K5/00 , H03K5/153

5. 发明专利

JPS61187424A DISTORTION COMPENSATION CIRCUIT 失效
公开(公告)号：JPS61187424A
公开(公告)日：1986-08-21
申请号：JP2703185
申请日：1985-02-14
申请人： FUJITSU LTD
发明人： FUKUGAHARA TSUTOMU , ICHIKAWA AKIHIKO , SHIMIZU KAZUYOSHI
IPC分类号： H03F1/32 , H04B1/04 , H04B3/10
摘要： PURPOSE:To cancel automatically deterioration of the characteristic of a device by measuring automatically a harmonic distortion of a pilot signal and using a differential amplifier so as to compensate a harmonic distortion generated between a transmitter and a receiver depending on the quantity of the distortion. CONSTITUTION:A transmission signal superimposed with a pilot signal is sent from the sending side. A differential amplifier 7 of a distortion compensating circuit 6 amplifies an output signal of a receiver 5, the distortion of the output is extracted by BPF 8 and a detector 9 converts it into a DC component. A comparator 10 controls an FET 11 when the DC component of the output of the detector 9 is larger than a reference voltage Vref. The FET11 acts like a variable resistive element and changes the value of the variable resistive element 11 in proportion to the degree that the said DC component is larger than the voltage Vref. As a result, an FET 13 acts like a distortion generating circuit to generate the distortion component. The component is fed to the differential amplifier 7 in opposite phase to the reception signal and the adjusted component is reduced.

6. 发明专利

JPS61182336A APD PROTECTING CIRCUIT 失效
公开(公告)号：JPS61182336A
公开(公告)日：1986-08-15
申请号：JP2237785
申请日：1985-02-07
申请人： FUJITSU LTD
发明人： SHIMIZU KAZUYOSHI , FUKUGAHARA TSUTOMU , ICHIKAWA AKIHIKO
IPC分类号： H04B10/00 , H03K17/78 , H04B10/07 , H04B10/2507 , H04B10/80
摘要： PURPOSE:To apply a stable voltage while limiting a bias current of an APD by providing a constant voltage source using a transistor (TR) between a high voltage DC source and the APD. CONSTITUTION:A base voltage of a TR 5 is fed from the high voltage DC source 1 via resistors 2 and 3, current limit is executed by a resistor 4, a voltage is applied to the APD 6 and an operational amplifier 7 and a resistor 8 consti tute a preamplifier. The TR 5 acts as an emitter follower. A voltage division circuit comprising the resistors 2 and 3 makes the base voltage VB to the TR 5 nearly constant and a collector current is fed via the resistor 4. Even when the collector voltage is increased due to any cause, the voltage drop is increased, the collector voltage is decreased and the emitter current is not increased, the bias current flowing to the APD 6 is limited and the APD 6 is actuated stably.

7. 发明专利

JPS60136437A HIGH FREQUENCY SUPERPOSING SYSTEM 失效
公开(公告)号：JPS60136437A
公开(公告)日：1985-07-19
申请号：JP25055583
申请日：1983-12-24
申请人： FUJITSU LTD , NIPPON TELEGRAPH & TELEPHONE
发明人： FUKUGAHARA TSUTOMU , HANANO NAOMASA , TAKAHASHI MASAAKI , FUJINO SHIYOUJI , NAGATA YOUICHI
IPC分类号： H04B10/60 , H01S5/042 , H04B10/00 , H04B10/2507 , H04B10/40 , H04B10/50 , H04B10/54
摘要： PURPOSE:To reduce easily generation of distortion by using plural frequencies higher and lower than the cut-off frequency of an optical fiber as a high frequency signal to be superposed to a transmission signal. CONSTITUTION:Outputs of plural oscillators OSC1-OSCn different in frequency are mixed in a hybrid circuit HYB. The transmission signal from a signal source SG is chopped in a switching circuit SW by the superposed signal outputted from the circuit HYB, and a bias is applied. As the result, frequency spectrums S21-S2n generated by oscillators OSC1-OSCn are distributed over a flat part and a slope part of a frequency characteristic C1 of the optical fiber. A laser diode LD is driven by the output having these spectrums, and a generated optical signal is inputted to an optical fiber OF. The high frequency S2n is superposed to reduce coherence of the laser light. Thus, generation of distortion is reduced though the frequency characteristic C1 is varied.

8. 发明专利

JPS60120609A HIGH-PASS FILTER 失效
公开(公告)号：JPS60120609A
公开(公告)日：1985-06-28
申请号：JP22837683
申请日：1983-12-05
申请人： FUJITSU LTD
发明人： TAKAHASHI MASAAKI , HANANO NAOMASA , FUKUGAHARA TSUTOMU , FUJINO SHIYOUJI
IPC分类号： H03H11/04
摘要： PURPOSE:To flatten group delay characteristics and eliminate the distortion of transmission characteristics by composing a high-pass filter of an optical fiber which has group delay characteristics. CONSTITUTION:An input IN is divided into two by a hybrid circuit 11; one is inputted to the 1st amplifier 12 and the other is inputted to the 3rd amplifier 18. The output of the 1st amplifier 12 is converted by a light emitting element 13 into light, which is transmitted through an optical fiber 14. It is converted by a photodetecting element 15 into an electric signal which is inputted to a subtracter 17 through the 2nd amplifier 16. The output of the 3rd amplifier 18, on the other hand, is inputted to the subtractor 17 directly. The light emitting element 13, optical fiber 14, and photodetecting element 15 have frequency characteristics shown by (1), (2), and (3) and the optical fiber 14 has the group delay characteristics. The frequency characteristics (4) of the input signal to the amplifier 18 are flat, so the output signal of the subtractor 17 has characteristics (5) and the group delay characteristics of the output are flattened as shown by (6).

9. 发明专利

JPS60117930A PHOTO-ELECTRIC CONVERSION CIRCUIT 失效
公开(公告)号：JPS60117930A
公开(公告)日：1985-06-25
申请号：JP22432783
申请日：1983-11-30
申请人： FUJITSU LTD
发明人： FUKUGAHARA TSUTOMU , HANANO NAOMASA , TAKAHASHI MASAAKI , FUJINO SHIYOUJI
IPC分类号： H04B10/2507 , H04B10/00 , H04B10/07 , H04B10/25
摘要： PURPOSE:To keep the output of an amplifier at a fixed level by performing the input feedback of the DC component of the output of a parallel feedback type amplifier via the 2nd amplifier. CONSTITUTION:The DC output Vout of an amplifier 30 serving as a parallel feedback type preamplifier is fed back to the input of the amplifier 30 through an amplifier 31. Then the value of a capacitor 40 is selected so that the response of the amplifier 31 is equal approximately to DC. When the Vout is lowered, the input of the amplifier 30 rises when it is fed back to the amplifier 30 via the amplifier 31. While the input of the amplifier 30 is lowered when the Vout rises.

10. 发明专利

JPS59190753A Two-way communication system 失效
标题翻译：双向通信系统
公开(公告)号：JPS59190753A
公开(公告)日：1984-10-29
申请号：JP6584983
申请日：1983-04-14
申请人： Fujitsu Ltd
发明人： HANANO NAOMASA , FUKUGAHARA TSUTOMU , TAKAHASHI MASAAKI , FUJINO SHIYOUJI
IPC分类号： H04L29/08 , H04L5/14 , H04L5/16
CPC分类号： H04L5/1484
摘要： PURPOSE:To attain synchronization by an easy method and send out data by sending a synchronizing bit out of one station, receiving and confirming it at the other station and returning a synchronizing bit, and confirming it at the former station and sending out the data. CONSTITUTION:A station A sends only the synchronizing bit F1 to a station B through a synchronizing bit sending means FT and a two-way communication path DTL. The station B receives it by a receiving means FR, and a synchronism detecting means S detects synchronism. When the synchronism is detected, the station B generates a synchronizing bit F2, which is sent out of a sending means FT to the station A. The station A receives it by a receiving means FR, and a synchronism detecting means S confirms the synchronizing bit to discriminates that information transmission between the stations A and B is synchronized, and sends out data DT to the station B. Thus, it is clarified securely in the early stage that signals of time-division multiplex communication between both stations are transmitted synchronously.
摘要翻译：目的：通过简单的方法实现同步，通过从一个站发送同步位发送数据，在另一个站点接收和确认，返回一个同步位，并在前一个站进行确认并发送数据。构成：站A通过同步位发送单元FT和双向通信路径DTL仅向站B发送同步位F1。站B由接收装置FR接收，同步检测装置S检测同步。当检测到同步时，站B产生从发送装置FT发送到站A的同步位F2。站A由接收装置FR接收它，同步检测装置S确认同步位识别站A和站B之间的信息传输同步，并将数据DT发送到站B.因此，在早期阶段就可以安全地说明两台站之间的时分复用通信信号是同步传输的。

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