JPS57133734A - Detection circuit for signal interruption - Google Patents

Detection circuit for signal interruption

Info

Publication number
JPS57133734A
JPS57133734A JP56019531A JP1953181A JPS57133734A JP S57133734 A JPS57133734 A JP S57133734A JP 56019531 A JP56019531 A JP 56019531A JP 1953181 A JP1953181 A JP 1953181A JP S57133734 A JPS57133734 A JP S57133734A
Authority
JP
Japan
Prior art keywords
circuit
interruption
signal
noise
signals
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.)
Granted
Application number
JP56019531A
Other languages
Japanese (ja)
Other versions
JPS6234303B2 (en
Inventor
Kazuo Yamaguchi
Motohide Takahashi
Toshitaka Tsuda
Takafumi Nakajo
Kenji Okada
Tsutomu Kamoto
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
Nippon Telegraph and Telephone Corp
Original Assignee
Fujitsu Ltd
Nippon Telegraph and Telephone Corp
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, Nippon Telegraph and Telephone Corp filed Critical Fujitsu Ltd
Priority to JP56019531A priority Critical patent/JPS57133734A/en
Publication of JPS57133734A publication Critical patent/JPS57133734A/en
Publication of JPS6234303B2 publication Critical patent/JPS6234303B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/693—Arrangements for optimizing the preamplifier in the receiver
    • H04B10/6931—Automatic gain control of the preamplifier

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Dc Digital Transmission (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Optical Communication System (AREA)

Abstract

PURPOSE:To achieve an optical digital transmission system which can surely detect interruption of signals, by using a differential output signal of a timing circuit. CONSTITUTION:At interruption of signals, the sum of a shot noise generated from an avalanche photodiode APD of a photoelectric conversion circuit and thermal noise generated from an equivalent amplifying circuit 2 is inputted to a timing circuit 4, and the said noise is amplified to a level equal to a signal level with an AGC circuit controlling an amplification factor of the APD. On the other hand, a level difference DELTA can be presented between the amplitude outputted at the minimum output amplitude of the output of a tank circuit 21 and the maximum noise amplitude caused by the noise at signal interruption by setting the gain alpha of a limiter circuit 22 to a suitable value. The interruption of signals can be detected, by detecting the level difference DELTA with a signal interruption detecting circuit 5 consisting of level shift circuits 24, 25, a comparison circuit 26, a peak detection circuit 27 and a comparison circuit 28.
JP56019531A 1981-02-12 1981-02-12 Detection circuit for signal interruption Granted JPS57133734A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56019531A JPS57133734A (en) 1981-02-12 1981-02-12 Detection circuit for signal interruption

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56019531A JPS57133734A (en) 1981-02-12 1981-02-12 Detection circuit for signal interruption

Publications (2)

Publication Number Publication Date
JPS57133734A true JPS57133734A (en) 1982-08-18
JPS6234303B2 JPS6234303B2 (en) 1987-07-25

Family

ID=12001914

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56019531A Granted JPS57133734A (en) 1981-02-12 1981-02-12 Detection circuit for signal interruption

Country Status (1)

Country Link
JP (1) JPS57133734A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007028038A (en) * 2005-07-14 2007-02-01 Renesas Technology Corp Semiconductor device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007028038A (en) * 2005-07-14 2007-02-01 Renesas Technology Corp Semiconductor device
JP4679278B2 (en) * 2005-07-14 2011-04-27 ルネサスエレクトロニクス株式会社 Semiconductor device

Also Published As

Publication number Publication date
JPS6234303B2 (en) 1987-07-25

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