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31. 发明专利

JP2000209038A HIGH FREQUENCY POWER AMPLIFIER AND RADIO COMMUNICATION EQUIPMENT 失效
公开(公告)号：JP2000209038A
公开(公告)日：2000-07-28
申请号：JP30042399
申请日：1999-10-22
申请人： HITACHI LTD , HITACHI ULSI SYS CO LTD , HITACHI TOBU SEMICONDUCTOR LTD
发明人： MARUYAMA MASASHI , AKAMINE HITOSHI , KOBORI TSUTOMU , MORIYAMA SHINJI
IPC分类号： H03F1/30 , H03F1/02 , H03F1/32 , H03F3/195 , H03F3/24
摘要： PROBLEM TO BE SOLVED: To improve distortion characteristics and to enhance the efficiency of an amplifier by providing first and second semiconductor amplifying elements and a bias circuit, and linearly changing resistance value on the high potential side of a resistance type potential dividing circuit so that temperature characteristics of idle current at the time of being not inputted from an input terminal become negative characteristics. SOLUTION: In a high frequency power amplifier module (high frequency power amplifier) incorporated with transistors in multiple stages, a resistor 15 on the high potential side of the resistance type potential dividing circuit (bias circuit) to be connected to the control terminal of each transistor is a temperature compensation type resistor to linearly change the resistance value. Therefore, when the temperature rises, the resistance value of the temperature compensation resistor is successively increased, the potential of a control electrode is lowered, and the temperature characteristics of the idle current become negative. The temperature of the resistor on the high potential side of the resistance potential dividing circuit is only compensated by the bias circuit of semiconductor amplifying elements on the first (input) stage and final (output) stage, and it is not necessary to attach any other component for fixing a drain current.

32. 发明专利

JPS6471281A SIGNAL DISCRIMINATOR 失效
公开(公告)号：JPS6471281A
公开(公告)日：1989-03-16
申请号：JP22634687
申请日：1987-09-11
申请人： HITACHI LTD
发明人： AKAMINE HITOSHI , MORO EIJI , TORII HIROYUKI , MIURA KUNIAKI
IPC分类号： G11B20/02 , G11B20/06 , H04N5/93
摘要： PURPOSE:To discriminate a reproduced FM signal without malfunction by using a HOLD control circuit holding the preceding state when an input signal is a signal having a prescribed threshold value or below and outputting the information of the signal when the level is the threshold value or over. CONSTITUTION:An input signal is inputted to a peaking circuit 1 and given to an automatic signal discriminator 4 after passing through AGC circuits 2, 3. The automatic signal discriminator 4 is added with a signal changeover time constant circuit at the S-VHS side comprising a resistor 15 and a capacitor 13 and a time constant circuit for signal changeover at the VHS side comprising a resistor 16 and a capacitor 14 after the signal comparison and detection. The signal inputted to the automatic signal discriminator 4 is subject to comparison and detection of FM spectrum and to which of the S-VHS or VHS system the signal belongs is discriminated and an output signal in matching therewith is outputted via a HOLD control circuit 12.

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