JPS5726940A - Agc circuit - Google Patents

Agc circuit

Info

Publication number
JPS5726940A
JPS5726940A JP10123080A JP10123080A JPS5726940A JP S5726940 A JPS5726940 A JP S5726940A JP 10123080 A JP10123080 A JP 10123080A JP 10123080 A JP10123080 A JP 10123080A JP S5726940 A JPS5726940 A JP S5726940A
Authority
JP
Japan
Prior art keywords
amplitude
input signal
optical input
voltage
noise
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
JP10123080A
Other languages
Japanese (ja)
Inventor
Toshiyuki Yamashita
Sadao Ifukuro
Masakazu Mori
Satoshi Ikeuchi
Yasuo Nagai
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 JP10123080A priority Critical patent/JPS5726940A/en
Publication of JPS5726940A publication Critical patent/JPS5726940A/en
Pending 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
    • 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
    • H04B10/691—Arrangements for optimizing the photodetector in the receiver
    • H04B10/6911—Photodiode bias control, e.g. for compensating temperature variations

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Light Receiving Elements (AREA)
  • Control Of Amplification And Gain Control (AREA)
  • Optical Communication System (AREA)

Abstract

PURPOSE:To reduce the variance of an output signal level due to noise, by controlling a bias voltage of photoelectric conversion element according to the amplitude of a DC component of an optical input signal. CONSTITUTION:A control means consisting of a DC/DC converter 14 having a constant output voltage is used for an input voltage having a constant value or more, voltage monitor circuit 34 and voltage controlled switch 32 are used. When the amplitude of an optical input signal is small, the AGC operation is made by detecting the DC component of the optical input signal through the use of a smoothing circuit 24 without peak detection, and the AGC operation by the peak detection is made if the amplitude of the optical input signal is greater, that is, the S/N is good, then the amplitude of the output signal can be avoided from being smaller than the specified value through noise, if the amplitude of the optical input signal is small and the S/N is worse.
JP10123080A 1980-07-25 1980-07-25 Agc circuit Pending JPS5726940A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10123080A JPS5726940A (en) 1980-07-25 1980-07-25 Agc circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10123080A JPS5726940A (en) 1980-07-25 1980-07-25 Agc circuit

Publications (1)

Publication Number Publication Date
JPS5726940A true JPS5726940A (en) 1982-02-13

Family

ID=14295091

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10123080A Pending JPS5726940A (en) 1980-07-25 1980-07-25 Agc circuit

Country Status (1)

Country Link
JP (1) JPS5726940A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2419247A (en) * 2004-10-18 2006-04-19 Agilent Technologies Inc Variable power supply filter for an optical transducer
KR100890293B1 (en) * 2004-08-18 2009-03-26 로무 가부시키가이샤 Gain adjustment circuit, signal processing circuit, and electric device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100890293B1 (en) * 2004-08-18 2009-03-26 로무 가부시키가이샤 Gain adjustment circuit, signal processing circuit, and electric device
GB2419247A (en) * 2004-10-18 2006-04-19 Agilent Technologies Inc Variable power supply filter for an optical transducer
US7309852B2 (en) 2004-10-18 2007-12-18 Avago Technologies Ecbu Ip (Singapore) Pte Ltd. Variable noise control for an optical transducer
GB2419247B (en) * 2004-10-18 2009-02-18 Agilent Technologies Inc Variable noise control for an optical transducer

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