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1. 发明专利

JP2006345341A AMPLIFIER 审中-公开
公开(公告)号：JP2006345341A
公开(公告)日：2006-12-21
申请号：JP2005170535
申请日：2005-06-10
申请人： HITACHI INT ELECTRIC INC , UNIV HOKKAIDO
发明人： TAKEDA YASUHIRO , OKUBO YOICHI , ADACHI MASARU , NOJIMA TOSHIO
IPC分类号： H03F1/07 , H03F3/68
摘要： PROBLEM TO BE SOLVED: To provide an amplifier which has the amplification efficiency improved to be able to be used in a wide frequency band in consideration of the issue that a conventional Doherty amplifier fails in optimum matching not to have amplification efficiency improved and doesn't allow the frequency band to be widened. SOLUTION: The amplifier includes a first amplification circuit operating as a class AB amplifier, a second amplification circuit operating as a class B or C amplifier, a composition point where an output of the first amplification circuit and that of the second amplification circuit are composited through an impedance converter comprising transmission line having electric lengths other than λ/4. The impedance converter has a plurality of transmission lines different by electric length and is capable of switching connection to one of transmission lines in accordance with a frequency of an input signal. COPYRIGHT: (C)2007,JPO&INPIT

2. 发明专利

JP2002009651A VARIABLE GAIN AMPLIFIER 失效
公开(公告)号：JP2002009651A
公开(公告)日：2002-01-11
申请号：JP2000192334
申请日：2000-06-27
申请人： HITACHI INT ELECTRIC INC
发明人： TAKEDA YASUHIRO
IPC分类号： H03F3/60 , H03G1/04 , H03G3/20 , H04B1/18 , H04B3/04 , H04B7/08
摘要： PROBLEM TO BE SOLVED: To solve the problem of the conventional variable gain amplifiers, employed for a diversity system receiver, that they cannot make the reception sensitivity of each branch constant because the noise figure (hereinafter referred to as NF) is deteriorated at a decreased gain and the NF of both the variable gain amplifiers is in dispersion, even if a common control voltage is made common to between the branches. SOLUTION: An input side matching circuit is connected to an input side of a voltage-controlled variable amplifier, whose amplification factor is varied with a control signal, and an output side matching circuit is connected to the output side, and the input side matching circuit and the output side matching circuit are controlled characteristically with the control signal.

3. 发明专利

JP2001094449A WIRELESS RECEIVER 失效
公开(公告)号：JP2001094449A
公开(公告)日：2001-04-06
申请号：JP26471199
申请日：1999-09-20
申请人： HITACHI INT ELECTRIC INC
发明人： TAKEDA YASUHIRO
IPC分类号： H04B1/26 , H04B1/10
摘要： PROBLEM TO BE SOLVED: To attain improvement on the spurious receiving sensitivity having been considered difficult, by adopting a frequency 45 MHz for a reception intermediate frequency. SOLUTION: The wireless receiver provided with a radio section, that receives a received radio wave via an antenna filter, amplifies the radio wave at a high frequency amplifier section, and processes the amplified signal via a reception filter, is provided with a 1st band pass filter, a 2nd band pass filter whose path band is different from that of the 1st band pass filter and a means that switches the two filters depending on the frequency in use so as to enhance the reception sensitivity of spurious radiation.

4. 发明专利

JP2003168987A RADIO TRANSMITTER 审中-公开
公开(公告)号：JP2003168987A
公开(公告)日：2003-06-13
申请号：JP2001364204
申请日：2001-11-29
申请人： HITACHI INT ELECTRIC INC
发明人： TAKEDA YASUHIRO , NAITO MASASHI
IPC分类号： H04B1/04 , H04B1/38
摘要： PROBLEM TO BE SOLVED: To provide a radio transmitter which always monitors a transmission signal and stops transmitting a radio signal when an analyzed result of the transmission signal does not satisfy the predetermined standards, to output an abnormality alarm. SOLUTION: A radio transmitter takes in communication system software and standard information from an external unit and transmits a radio signal formed based on the communication system software. A distributor 203 distributes the radio signal output from a transmission part 105 to the external unit and a spectrum analysis part 204, which frequency-analyzes the radio signal based on the standard information. A power comparison part 205 compares a result of the frequency analysis with the standard information and determines whether to enable the transmission of the radio signal. If the determined result is to enable the transmission of the radio signal, A CPU 201 transmits the radio signal, and if the determined result is not to enable the transmission of the radio signal, the CPU 201 stops transmitting the radio signal, and an alarm output part 206 outputs an abnormality alarm according to instructions of the CPU 201. COPYRIGHT: (C)2003,JPO

5. 发明专利

JP2002217660A VARIABLE GAIN AMPLIFIER CIRCUIT 失效
公开(公告)号：JP2002217660A
公开(公告)日：2002-08-02
申请号：JP2001008583
申请日：2001-01-17
申请人： HITACHI INT ELECTRIC INC
发明人： TAKEDA YASUHIRO
IPC分类号： H03F1/08 , H03G1/04 , H03G3/20 , H03G3/30
摘要： PROBLEM TO BE SOLVED: To solve the problem in that the noise figure is deteriorated when the gain is lowered in a variable gain amplifier of a variable gain amplifier circuit. SOLUTION: The variable gain amplifier circuit includes a variable gain amplifier for varying the amplifying degree through a gain control signal, an input-side matching unit connected on the input side of the variable gain amplifier, an output-side matching unit connected on the output side of the variable gain amplifier, and a controller for receiving the output signal of the variable gain amplifier and generating a matching control signal for controlling the gain control signal, the input-side matching unit and the output-side matching unit. In this case, the input-side matching unit and the output-side matching unit consist of a varicap capacitor and a variable coil.

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