JPS5778239A - Automatic gain adjusting system - Google Patents

Automatic gain adjusting system

Info

Publication number
JPS5778239A
JPS5778239A JP55153117A JP15311780A JPS5778239A JP S5778239 A JPS5778239 A JP S5778239A JP 55153117 A JP55153117 A JP 55153117A JP 15311780 A JP15311780 A JP 15311780A JP S5778239 A JPS5778239 A JP S5778239A
Authority
JP
Japan
Prior art keywords
signal
constant
output
level
optical
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
JP55153117A
Other languages
Japanese (ja)
Inventor
Masakazu Mori
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 JP55153117A priority Critical patent/JPS5778239A/en
Publication of JPS5778239A publication Critical patent/JPS5778239A/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
    • H04B10/25—Arrangements specific to fibre transmission

Landscapes

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

Abstract

PURPOSE:To prevent degradation of the SN ratio, by chopping an optical output by a constant frequency in the outside of the analogue signal transmission band to transmit it in a constant level and by detecting a minimum level after photoelectric conversion in the receiving side to control the gain of a receiver so that the level becomes constant. CONSTITUTION:In the transmission side, a laser diode is modulated by an analogue signal, and simultaneously, the signal is chopped through a chopper circuit 2 by a frequency in the outside of the analogue signal transmission band. For the purpose of setting a minimum level P0 of the optical output to a constant value in the laser beam emussion region, the output of a light emitter 7 is received by a light receiver 6, and a minimum potential is detected in a 4 and is so controlled that it becomes a reference potential 8, and an optical signal is transmitted. In the receiving side, the optical signal is received in the 6 and is converted to an electric signal, and a minimum level P1 is detected in the 4 and is compared with the reference potential 8 in a 5, and the output is converted to an optimum value by a DC-DC converter 13 to control the gain automatically in a 10. Thus, the automatic gain control is possible without superposing a pilot signal, and the shot noise due to superposition of the pilot signal is eliminated.
JP55153117A 1980-10-31 1980-10-31 Automatic gain adjusting system Pending JPS5778239A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP55153117A JPS5778239A (en) 1980-10-31 1980-10-31 Automatic gain adjusting system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP55153117A JPS5778239A (en) 1980-10-31 1980-10-31 Automatic gain adjusting system

Publications (1)

Publication Number Publication Date
JPS5778239A true JPS5778239A (en) 1982-05-15

Family

ID=15555335

Family Applications (1)

Application Number Title Priority Date Filing Date
JP55153117A Pending JPS5778239A (en) 1980-10-31 1980-10-31 Automatic gain adjusting system

Country Status (1)

Country Link
JP (1) JPS5778239A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008026183A1 (en) * 2006-08-31 2008-03-06 Koninklijke Philips Electronics N.V. Cavity-enhanced photo acoustic trace gas detector with improved feedback loop

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008026183A1 (en) * 2006-08-31 2008-03-06 Koninklijke Philips Electronics N.V. Cavity-enhanced photo acoustic trace gas detector with improved feedback loop
JP2010502944A (en) * 2006-08-31 2010-01-28 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Cavity-enhanced photoacoustic trace gas detector with improved feedback loop
US8109128B2 (en) 2006-08-31 2012-02-07 Koninklijke Philips Electronics N.V. Cavity-enhanced photo acoustic trace gas detector with improved feedback loop

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