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1. 发明专利

JPH08314553A CONSTANT VOLTAGE CIRCUIT 失效
公开(公告)号：JPH08314553A
公开(公告)日：1996-11-29
申请号：JP14128095
申请日：1995-05-15
申请人： HITACHI LTD , HITACHI TOBU SEMICONDUCTOR LTD
发明人： SATO TETSUO , IENAKA MASANORI , KUDO KATSUMI
IPC分类号： G05F3/26 , G05F1/56
摘要： PURPOSE: To obtain constant voltage output to a voltage very near the voltage value of an original power source by simple constitution by comparing a reference voltage and an output voltage, forming an output current, which becomes a constant voltage according to the reference voltage, and supplying it to a current mirror circuit by means of a voltage comparing and current converting circuit so as to form an output voltage. CONSTITUTION: An unstable power source VB supplied from an external terminal is supplied to the emitter of a PNP transistor Q2 constituting the current mirror circuit as a current amplifier circuit to output a constant voltage V0 from the collector of the transistor Q2. A PNP transistor Q1 making a pace and the emitter common with the transistor Q2 is connected to the transistor Q2 in the form of a current mirror. Then the output voltage V0 is supplied to the reverse input-of an amplifier circuit AMP which executes voltage comparison and voltage-current conversion and the constant voltage VC is supplied to the nonreverse input +. Thereby the amplifier circuit AMP compares the constant voltage VC and the output voltage V0 to form a current signal corresponding to the voltage difference.

2. 发明专利

JPS6180906A Amplifier circuit 失效
标题翻译：放大器电路
公开(公告)号：JPS6180906A
公开(公告)日：1986-04-24
申请号：JP20178084
申请日：1984-09-28
申请人： Hitachi Ltd , Hitachi Tobu Semiconductor Ltd
发明人： SATO TETSUO , TSUCHIYA KENICHI
IPC分类号： H03F1/34 , H03F3/45
CPC分类号： H03F3/45071
摘要： PURPOSE:To make a phase capacitor and a DC cut capacitor unnecessary, and to improve a degree of integration of an IC by using an amplifier circuit as a composite differential circuit of a - power source consisting of a differential amplifier stage and an emitter follower stage. CONSTITUTION:The titled circuit is constituted so that an emitter follower stage consisting of a transistor (TR) Q5 which has connected an output load R1 to an emitter is provided on the next stage of a differential amplifier constituted of TRs Q1 and Q2, an output Vout is fetched from the emitter follower stage, and also this output is brought to a negative feedback to the other input terminal of the differential amplifier, and it is operated by a power source + Vcc. As a result, an open loop voltage gain of an amplifier circuit becomes small, and an oscillation preventing capacitor becomes unnecessary. Also, the negative feedback is executed through the emitter follower, therefore, a DC cutting capacitor of the differential amplifier becomes unnecessary, and a degree of integration of an IC can be improved.
摘要翻译：目的：为了使相位电容器和直流切割电容器不必要，并且通过使用放大器电路作为由差分放大器级和射极跟随器级组成的电源的复合差分电路来提高IC的集成度。构成：标题电路被构造成使得由将输出负载R1连接到发射极的晶体管（TR）Q5组成的射极跟随器级设置在由TR Q1和Q2构成的差分放大器的下一级上，输出 Vout从射极跟随器级获取，并且该输出也被送到差分放大器的另一输入端的负反馈，并由电源+ Vcc操作。结果，放大器电路的开环电压增益变小，并且不需要防振荡电容器。此外，通过射极跟随器执行负反馈，因此，不需要差分放大器的DC切割电容器，并且可以提高IC的集成度。

3. 发明专利

DE3586363D1 未知
公开(公告)号：DE3586363D1
公开(公告)日：1992-08-27
申请号：DE3586363
申请日：1985-03-21
申请人： HITACHI LTD
发明人： NODA TSUTOMU , ISO YOSHIMI , SATO TETSUO
IPC分类号： G11B20/00 , G11B20/10 , H03M1/00 , H03M1/82
摘要： A digital-to-analogue converter for use in a digitally-recorded-signal reproducing apparatus comprises a first constant current source (5, 11, 12; 42, 43, 44), a switch (4; 13, 14; 45, 46, 47) for allowing the constant current of the first constant current source to flow therethrough for a period corresponding to the digital data, a second constant current source (26; 36; 55; 60) generating a current flowing in the direction opposite to that of the current generated by the first constant current source, a switch (27; 37; 56; 61) for allowing the current of the second constant current source to flow therethrough for a predetermined constant period, and an integrator (7,8,9), wherein the sum of the first and second constant currents is integrated by the integrator. The analogue signal outputted by the integrater has a center level in the vicinity of the ground potential level.

4. 发明专利

IT1135612B 未知
公开(公告)号：IT1135612B
公开(公告)日：1986-08-27
申请号：IT1995781
申请日：1981-02-24
申请人： HITACHI LTD
发明人： KOMINAMI YASUO , SATO TETSUO , OHKUBO YUICHI
IPC分类号： H03G9/02 , H03F
摘要： Either an input signal of a combining network or an output signal of an inverter arranged on a main path is fed to a side path through a mode switch in a switchable signal compressor/signal expander. Since an input terminal of a control amplifier is connected to a variable filter without passing through a signal amplifier, the deviation of the detection characteristic of a rectifier and integrator attributed to D.C. offset voltages of the signal amplifier and the control amplifier can be reduced. On the other hand, a switchable signal compressor/signal expander in another aspect of performance has a reference voltage generator for producing a D.C. reference voltage, and the output D.C. level of the control amplifier is maintained at a level approximate to the D.C. reference voltage. The other ends of first and second capacitors of the rectifier and integrator are also supplied with the D.C. reference voltage, so that the fluctuation of the detection characteristic of the rectifier and integrator ascribable to the fluctuation of the D.C. reference voltage is reduced.

5. 发明专利

IT8119839D0 未知
公开(公告)号：IT8119839D0
公开(公告)日：1981-02-18
申请号：IT1983981
申请日：1981-02-18
申请人： HITACHI LTD
发明人： SATO TETSUO , KOMINAMI YASUO
IPC分类号： G11B20/02 , G11B23/00 , H03G9/02 , G11B
摘要： A recording/playing circuit includes a noise reduction circuit, a switching circuit and a control circuit. The noise reduction circuit includes a pre-amplifier, a combining network, an inverter circuit and a side chain. The switching circuit has first, second and third input positions and an output terminal. The first input position is coupled to the output of the pre-amplifier, the second input position is coupled to the output of the inverter circuit, and the output terminal is coupled to the side chain. The third input position is connected to a muting circuit. The control circuit controls the switching circuit so that one of the electric signals applied to the first, second and third input positions of the switching circuit may be selectively transmitted to the output terminal of the switching circuit.

6. 发明专利

DE2929469A1 未知
公开(公告)号：DE2929469A1
公开(公告)日：1980-02-28
申请号：DE2929469
申请日：1979-07-20
申请人： HITACHI LTD
发明人： SATO TETSUO
IPC分类号： H03J7/28 , H03J5/00 , H03J5/02 , H04B1/26
摘要： A selecting information for adjusting the frequency-dividing ratio of a programable divider in a PLL synthesizer tuner is stored in the memory. In order to prevent the same selecting information from being written down in the different addresses in the memory, all of the selecting informations already written down in the memory is compared with the selecting information that is to be written down by a comparator circuit before the selecting information is written down in the memory. The output of the comparator circuit permis the selecting information to be written into the new addresses only when the selecting information that is to be written down is different from all of the selecting informations which have been written down already.

7. 发明专利

GB2138231B SIGNAL TRANSMISSION CIRCUIT 未知
公开(公告)号：GB2138231B
公开(公告)日：1986-10-15
申请号：GB8400522
申请日：1984-01-10
申请人： HITACHI LTD
发明人： WATANABE KAZUO , SATO TETSUO
IPC分类号： G11B5/02 , G11B5/035 , G11B20/24 , H03G3/10 , H03H19/00 , H04B3/04 , G11B5/45
摘要： A signal transmission circuit includes a switched capacitor and a control circuit. The switched capacitor includes a capacitor and a plurality of switching means. The control circuit controls the frequency or level of a control signal to be applied to the switching means of the switched capacitor. By varying the frequency of the control signal with the control circuit, the equivalent resistance of the switched capacitor can be varied. By controlling the level of the control signal with the control circuit, at least one of the plurality of switching means is held in the "off" state thereof, to substantially inhibit the signal transmission of the switched capacitor.

8. 发明专利

HK37385A A VOLTAGE CONTROLLED VARIABLE GAIN CIRCUIT AND A SIGNAL TRANSMISSION CIRCUIT INCORPORATING SAME 未知
公开(公告)号：HK37385A
公开(公告)日：1985-05-24
申请号：HK37385
申请日：1985-05-16
申请人： HITACHI LTD
发明人： SATO TETSUO
IPC分类号： H03G1/00 , H03G1/04 , H03G3/02 , H03G3/12 , H03G3/00
摘要： An integrated voltage control variable gain circuit capable of exhibiting, when the external circuit network is connected in a first configuration, a low distortion factor of the output signal, and capable of effecting, when the external circuit network is connected in a second configuration, independent controls of gains for different two input signals. The integrated voltage control variable gain circuit is provided, in its integrated part, with a first operational amplifier circuit, a second operational amplifier circuit, a third operational amplifier circuit, a fourth operational amplifier circuit, a fifth operational amplifier circuit, a first gain control section and a second gain control section. The first operational amplifier circuit, the first gain control section and the third operational amplifier circuit are arranged in a first signal line, while, in the second signal line, arranged are the second operational amplifier circuit, the second gain control section and the fourth operational amplifier circuit. It is possible to select whether the fifth operational amplifier circuit is disposed on the second signal line, by selecting the configurations of the external circuit network.

9. 发明专利

DE3230429A1 未知
公开(公告)号：DE3230429A1
公开(公告)日：1983-03-10
申请号：DE3230429
申请日：1982-08-16
申请人： HITACHI LTD , PIONEER ELECTRONIC CORP
发明人： SATO TETSUO , KOMINAMI YASUO , TAKIZAWA YOSHIYUKI , HAENO AKIRA
IPC分类号： H03G3/10 , H03F3/45 , H03H11/02 , H03H11/46
摘要： An electronic impedance circuit is constructed of a voltage-current converter and a variable gain current amplifier. The voltage-current converter includes first and second transistors of the PNP-type differentially connected. The variable gain current amplifier includes third and fourth transistors of the NPN-type differentially connected, and fifth and sixth transistors of the PNP-type as load means. The bases of the third and fourth transistors are respectively driven by collector signals of the first and second transistors, and a collector signal of the third transistor is fed back to the base of the second transistor. In order to reduce a d.c. offset attributed to a current flowing between the base of the second transistor and the collector of the third transistor, a compensation circuit is connected to the variable gain amplifier. This compensation circuit can provide compensation by producing a compensation current for cancelling the current between the base of the second transistor and the collector of the third transistor.

10. 发明专利

GB2104325A A VARIABLE ELECTRONIC IMPEDANCE CIRCUIT 未知
公开(公告)号：GB2104325A
公开(公告)日：1983-03-02
申请号：GB8220341
申请日：1982-07-13
申请人： HITACHI LTD
发明人： SATO TETSUO
IPC分类号： H03F1/00 , H03F1/30 , H03G7/00 , H03H11/46
摘要： A variable electronic impedance circuit is constructed of a voltage-current converter whose input terminal is supplied with an input signal voltage, and a variable-gain current amplifier whose input terminal is supplied with an output current of the voltage-current converter and whose output signal current is fed back to the input terminal of the voltage-current converter. In order to prevent the undesirable oscillation phenomenon of the variable electronic impedance circuit immediately after the closure of a power supply, a control circuit which operates for a predetermined time after the closure of the power supply is especially arranged. Since an output signal from the control circuit inhibits the operation of the variable-gain current amplifier during the predetermined time, the unstable operation immediately after the closure of the power supply can be prevented.

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