JPS5471592A - Monitoring system of light receiving levels - Google Patents

Monitoring system of light receiving levels

Info

Publication number
JPS5471592A
JPS5471592A JP13785477A JP13785477A JPS5471592A JP S5471592 A JPS5471592 A JP S5471592A JP 13785477 A JP13785477 A JP 13785477A JP 13785477 A JP13785477 A JP 13785477A JP S5471592 A JPS5471592 A JP S5471592A
Authority
JP
Japan
Prior art keywords
noise
light input
light receiving
temperature compensation
compared
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP13785477A
Other languages
Japanese (ja)
Inventor
Takashi Kihara
Satoshi Ikeuchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP13785477A priority Critical patent/JPS5471592A/en
Publication of JPS5471592A publication Critical patent/JPS5471592A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE: To monitor light input levels readily without using temperature compensation at all by detecting the noises produced within the light receiving system.
CONSTITUTION: The output of a DC reproducer 3 is separated to signal and noise by LPF 6 and HPF 7. Since the noise contains higher frequency bands as compared to the signal, only the noise may by readily drawn out. After sufficient amplification of the noise, the noise mean value is detected by performing rectifying and smoothing and said value is compared with a reference voltage. An alarm is given wben it exceeds the refernse voltage. Since there is a specified relation between the effective value of the shot noise which an avalanche photo diode produces and light input, monitoring of the shot noise eliminates the need for temperature compensation and the light input levels may be monitored by the simple circuits.
COPYRIGHT: (C)1979,JPO&Japio
JP13785477A 1977-11-18 1977-11-18 Monitoring system of light receiving levels Pending JPS5471592A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13785477A JPS5471592A (en) 1977-11-18 1977-11-18 Monitoring system of light receiving levels

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13785477A JPS5471592A (en) 1977-11-18 1977-11-18 Monitoring system of light receiving levels

Publications (1)

Publication Number Publication Date
JPS5471592A true JPS5471592A (en) 1979-06-08

Family

ID=15208329

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13785477A Pending JPS5471592A (en) 1977-11-18 1977-11-18 Monitoring system of light receiving levels

Country Status (1)

Country Link
JP (1) JPS5471592A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012000755A1 (en) * 2010-06-30 2012-01-05 Siemens Aktiengesellschaft Absolutely secure signal transmission by means of thermal noise

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012000755A1 (en) * 2010-06-30 2012-01-05 Siemens Aktiengesellschaft Absolutely secure signal transmission by means of thermal noise

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