JPS56164642A - Optical digital transmitter - Google Patents

Optical digital transmitter

Info

Publication number
JPS56164642A
JPS56164642A JP6713180A JP6713180A JPS56164642A JP S56164642 A JPS56164642 A JP S56164642A JP 6713180 A JP6713180 A JP 6713180A JP 6713180 A JP6713180 A JP 6713180A JP S56164642 A JPS56164642 A JP S56164642A
Authority
JP
Japan
Prior art keywords
circuit
level
comparator
automatic
chopping
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
JP6713180A
Other languages
Japanese (ja)
Inventor
Hiroyuki Fujita
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP6713180A priority Critical patent/JPS56164642A/en
Publication of JPS56164642A publication Critical patent/JPS56164642A/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
    • H04B10/50—Transmitters

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Semiconductor Lasers (AREA)
  • Optical Communication System (AREA)

Abstract

PURPOSE:To operate an automatic chopping circuit correctly, by giving a hysteresis characteristic to a circuit where the comparison with the reference value of an automatic chopping circuit is made, and keeping the light source in a chopped state even if the input level of the comparison circuit is changed after being chopped once. CONSTITUTION:An LD(semiconductor laser)2 is driven with a driving circuit 1 according to an input signal. Further, it is monitored by a photodiode 3 and an LD level is detected by a peak detecting circuit 5. This level is fed to an APC (automatic output controlling circuit)6 and feedback is given to the circuit 1. On the other hand, the peak value level is inputted to a comparator 8 having hysteresis to be compared with the reference value, and if the peak level is low, the input signal is cut off with a chopping gate 9 and deteriorated LDs are chopped. After that, although the input to the comparator 8 is increased up to a pseudo output level by a protection circuit 10, since the upper-limit threshold level is set higher than the pseudo output level, the output of the comparator 8 is not changed, allowing to complete the automatic chopping of an LD2 smoothly.
JP6713180A 1980-05-22 1980-05-22 Optical digital transmitter Pending JPS56164642A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6713180A JPS56164642A (en) 1980-05-22 1980-05-22 Optical digital transmitter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6713180A JPS56164642A (en) 1980-05-22 1980-05-22 Optical digital transmitter

Publications (1)

Publication Number Publication Date
JPS56164642A true JPS56164642A (en) 1981-12-17

Family

ID=13336031

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6713180A Pending JPS56164642A (en) 1980-05-22 1980-05-22 Optical digital transmitter

Country Status (1)

Country Link
JP (1) JPS56164642A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6021585A (en) * 1983-07-15 1985-02-02 Hitachi Koki Co Ltd Laser diode control circuit
JPS6068683A (en) * 1983-08-30 1985-04-19 Yokogawa Hewlett Packard Ltd Laser protecting circuit

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6021585A (en) * 1983-07-15 1985-02-02 Hitachi Koki Co Ltd Laser diode control circuit
JPS6068683A (en) * 1983-08-30 1985-04-19 Yokogawa Hewlett Packard Ltd Laser protecting circuit
JPH0348674B2 (en) * 1983-08-30 1991-07-25 Hewlett Packard Co

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