JPS5471592A - Monitoring system of light receiving levels - Google Patents
Monitoring system of light receiving levelsInfo
- 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
Links
Landscapes
- Light Receiving Elements (AREA)
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
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)
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 |
-
1977
- 1977-11-18 JP JP13785477A patent/JPS5471592A/en active Pending
Cited By (1)
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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