JPH0466822U

JPH0466822U -

Info

Publication number: JPH0466822U
Application number: JP10832290U
Authority: JP
Priority date: 1990-10-16
Filing date: 1990-10-16
Publication date: 1992-06-12
Anticipated expiration: 2005-10-16
Also published as: JP2578934Y2

Description

[Brief explanation of the drawing]

第１図は本考案を概念的に示すブロツク図、第
２図は本考案の第１実施例を示す要部の回路図、
第３図は同実施例の受光回路の周波数特性図、第
４図は本考案の第２実施例を示す要部の回路図、
第５図は本考案の第３実施例を示す要部の回路図
、第６図は本考案の第４実施例を示す要部の回路
図、第７図はＬＣＲ並列共振回路の変形例を示す
回路図である。図面中、１は受光信号増幅回路、４はトラツプ
特性増幅回路、５はフオトダイオード、１１はト
ランジスタ、１７はＬＣＲ並列共振回路、３１は
受光増幅回路、３４はフオトダイオード、４５は
トランジスタ、５０はＬＣＲ並列共振回路、５１
はトラツプ特性増幅回路、６１は受光信号増幅回
路、８０，８１は第１及び第２のトラツプ特性増
幅回路、８２はトランジスタ、８９はトランジス
タ、９４は第２のＬＣＲ並列共振回路、１０１は
受光信号増幅回路、１１２はトランジスタ、１１
７は第１のＬＣＲ並列共振回路、１２１は第２の
ＬＣＲ並列共振回路、１２２はトラツプ特性増幅
回路である。 Fig. 1 is a block diagram conceptually showing the present invention, Fig. 2 is a circuit diagram of the main part showing the first embodiment of the present invention,
FIG. 3 is a frequency characteristic diagram of the light receiving circuit of the same embodiment, and FIG. 4 is a circuit diagram of the main part showing the second embodiment of the present invention.
Fig. 5 is a circuit diagram of the main part showing the third embodiment of the present invention, Fig. 6 is a circuit diagram of the main part showing the fourth embodiment of the invention, and Fig. 7 is a modification of the LCR parallel resonant circuit. FIG. In the drawing, 1 is a photodetection signal amplification circuit, 4 is a trap characteristic amplification circuit, 5 is a photodiode, 11 is a transistor, 17 is an LCR parallel resonant circuit, 31 is a photodetection amplification circuit, 34 is a photodiode, 45 is a transistor, and 50 is a photodetection amplifier circuit. LCR parallel resonant circuit, 51
61 is a trap characteristic amplification circuit, 80 and 81 are first and second trap characteristic amplification circuits, 82 is a transistor, 89 is a transistor, 94 is a second LCR parallel resonant circuit, 101 is a received light signal an amplifier circuit, 112 a transistor, 11
7 is a first LCR parallel resonant circuit, 121 is a second LCR parallel resonant circuit, and 122 is a trap characteristic amplifier circuit.

Claims

[Claims for Utility Model Registration] 1. A light-receiving signal amplification circuit having low-frequency cutoff characteristics;
an emitter-grounded or source-grounded trap characteristic amplification circuit formed by inserting an LCR parallel resonant circuit between the emitter or source of a transistor and a ground line; A light-receiving circuit characterized in that the light-receiving circuit is set to be located at the foot of a frequency characteristic curve that exhibits low-frequency cutoff characteristics. 2. A received light signal amplification circuit having high-frequency cutoff characteristics;
an emitter-grounded or source-grounded trap characteristic amplification circuit in which an LCR parallel resonant circuit is inserted between the emitter or source ground line of a transistor, and the resonant frequency of the LCR parallel resonant circuit is higher than that of the light-receiving signal amplification circuit. 1. A light-receiving circuit characterized in that the light-receiving circuit is set to be located at the foot of a frequency characteristic curve exhibiting a frequency cut-off characteristic. 3. A light receiving signal amplification circuit having bandpass characteristics;
A first trap characteristic amplification circuit with a common emitter or common source, which is formed by inserting a first LCR parallel resonant circuit between the emitter or source of the transistor and the ground line, and between the emitter or source of the transistor and the ground line. second LCR to
a second trap characteristic amplification circuit with a grounded emitter or a common source formed by inserting a parallel resonant circuit, wherein each resonant frequency of the first and second LCR parallel resonant circuits passes through the band of the received light signal amplification circuit. 1. A light-receiving circuit characterized in that the light-receiving circuit is set to be located at each foot of a high-frequency side and a low-frequency side of a frequency characteristic curve showing characteristics. 4. A light receiving signal amplification circuit having bandpass characteristics;
an emitter-grounded or source-grounded trap characteristic amplifier circuit formed by inserting two first and second LCR parallel resonant circuits in series between the emitter or source of the transistor and the ground line; Each resonant frequency of the LCR parallel resonant circuit No. 2 is set to be located at each foot of a high-frequency side and a low-frequency side of a frequency characteristic curve indicating a bandpass characteristic of the light-receiving signal amplification circuit. light receiving circuit.