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公开(公告)号：JPH0457405A
公开(公告)日：1992-02-25
申请号：JP16879990
申请日：1990-06-26
发明人： KATO AKIRA
摘要： PURPOSE:To realize a hybrid circuit operated over a wide band by terminating a load end with a load circuit having a reactive impedance to correct a phase difference of signals outputted to 1st and 2nd output terminals. CONSTITUTION:Bifilar windings in pairs forming two inductors L1, L2 are wound close to each other on a troidal core, a capacitor C1 is connected between one-terminals of the inductors and a capacitor C2 connected between the other terminals of the inductors. Let both the terminals of the inductor L1 be P1, P2, and both the terminals of the inductor L2 be P3, P4, then the ports P2, P3 connect to ground via termination resistors RL1, RL2, and the port P4 connects to ground via a load circuit 20 having a reactive impedance component comprising series connection of a resistor Ro and an inductor Lo. A high frequency signal inputted to the port P1 is distributed into two, output signals whose phase difference is 90 deg. are outputted to the ports P2, P3 and the load circuit 20 acts like an element correcting the phase of the output signals so that the phase difference of them is almost 90 deg. over a broad frequency band.
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公开(公告)号：JPH0371725A
公开(公告)日：1991-03-27
申请号：JP20700689
申请日：1989-08-11
申请人： FUJITSU LTD
发明人： TAKATO KENJI , TOJO TOSHIRO , YAMAMOTO YUZO
摘要： PURPOSE:To obtain a hybrid circuit suitable for large scale integration by forming a transformer function section as electronic circuits. CONSTITUTION:A reception side mirror circuit 21R is constituted of an B line side mirror circuit MB which receives a reception side input current corresponding to a reception side 4-wire signal 4MR at a 1st terminal 1 and a reception side output current equivalent to the reception side input current is given to a B-line from a 2nd terminal 2 and is provided with a common terminal C outputting the sum of the reception side input current and the reception side output current and an A line side mirror circuit MA which shares the common terminal C, supplies the reception side input current to a 2nd terminal 2 and supplies the reception side output current equivalent to the reception side input current from a 1st terminal 1 in pairs. Then a transmission side mirror circuit 21S receives a transmission side current at the 1st terminal 1 with the common terminal C connected to the B line and generates a transmission side 4-wire signal 4WS equivalent to the transmission side current to a 2nd terminal 2. Thus, the transformer function section is realized by electronic circuits to attain large scale integration.
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公开(公告)号：JPH038139B2
公开(公告)日：1991-02-05
申请号：JP14917581
申请日：1981-09-21
申请人： NIPPON ELECTRIC CO
发明人： SHIMIZU HIROSHI
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公开(公告)号：JPH0247908B2
公开(公告)日：1990-10-23
申请号：JP21973583
申请日：1983-11-22
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公开(公告)号：JPH02226819A
公开(公告)日：1990-09-10
申请号：JP4691889
申请日：1989-02-28
申请人： FUJITSU LTD
发明人： YAMAMOTO KUNIO
摘要： PURPOSE:To improve calling quality and to save the labor for the selective setting operation of a balanced network by comparing the effects of plural selectable balanced networks provided on a subscriber circuit at the time of off-hook operation and deciding the best balanced network, and setting it automatically. CONSTITUTION:A decision control means 10 receives the outputs of a sent voice energy measuring means 8 and a received voice energy measuring means 9 and compares received voice energy values when detecting the sent voice energy being larger than a constant value to decide that the balanced network 6a, 6b, or 6c coupled with the differential amplifier 7a, 7b, or 7c which outputs the lowest voice energy is the best balanced network for a line to be measured, thereby semisetting the corresponding balanced network among the plural balanced networks 2a-2c in the subscriber circuit 1 in the subscriber circuit 1. Therefore, the balanced networks 2a-2c are selected and set automatically according to the variation of line conditions. Consequently, the calling quantity is improved and the labor for the selective setting operation of the balanced networks is saved.
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公开(公告)号：JPH02200017A
公开(公告)日：1990-08-08
申请号：JP2023489
申请日：1989-01-30
申请人： NEC CORP
发明人： ITO YUICHI
摘要： PURPOSE:To always set an optimally balanced impedance by computing the differential signal between a signal at one terminal of a subscriber line and the signal at a junction between a balanced impedance circuit and a terminal resistance, and generating a control voltage based on an amplitude display signal from a digital signal processing circuit. CONSTITUTION:When a positive and negative alternating signal is inputted to a transmission edge 10 as a training signal, the signals is inputted to a subtracter 6, converted into a digital signal by an A/D converter, inputted to a digital signal processing circuit 8, the control voltage is generated based on an amplitude display signal from the digital signal processing circuit 8, and outputted to a balanced impedance circuit 5. In such a case, by holding and outputting the controlled voltage generated in a controlled voltage generating circuit 9 at the time of training, even in a normal operating state, a balanced impedance Zb is differentiated from a value set at the time of training, and a near-end echo is suppressed. Thus even when the conditions of the subscriber line are changed, the optimally balanced impedance can be always set conforming to the respective conditions.
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公开(公告)号：JPH01231435A
公开(公告)日：1989-09-14
申请号：JP29856088
申请日：1988-11-25
申请人： NEC CORP
发明人： TAKAHASHI IKUHIRO
IPC分类号： H04B3/03
摘要： PURPOSE:To attain switching setting with high accuracy and to make the entire constitution small in size by forming a termination impedance matching with the characteristic impedance of a relay line according to an external command in response to the characteristic impedance of plural kinds of relay lines. CONSTITUTION:Transfer functions K, H of two amplifiers 12, 13, and a transfer function G of a voltage division circuit are calculated for each of plural kinds of characteristic impedances, and plural kinds of high resistance values are set to a resistance of each circuit, that is, ground resistors 23-26 of a feedback circuit of the amplifiers 12, 13 and each of branch resistors 21, 22 of a voltage division circuit and the plural kinds of resistances are selected switchingly by semiconductor switches 14, 15 by an external command. Thus, the termination impedance of a relay line 50 is always set stably. Thus, switching is set with high accuracy and the entire size is made small.
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