JPS55100760A - Signal-discontinuance detection circuit of photo pcm receiver - Google Patents

Signal-discontinuance detection circuit of photo pcm receiver

Info

Publication number
JPS55100760A
JPS55100760A JP902579A JP902579A JPS55100760A JP S55100760 A JPS55100760 A JP S55100760A JP 902579 A JP902579 A JP 902579A JP 902579 A JP902579 A JP 902579A JP S55100760 A JPS55100760 A JP S55100760A
Authority
JP
Japan
Prior art keywords
signal
photo
pcm
discontinuance
receiver
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
JP902579A
Other languages
Japanese (ja)
Other versions
JPS592212B2 (en
Inventor
Sadao Ifukuro
Kazuo Yamaguchi
Etsugo Yoneda
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 JP54009025A priority Critical patent/JPS592212B2/en
Publication of JPS55100760A publication Critical patent/JPS55100760A/en
Publication of JPS592212B2 publication Critical patent/JPS592212B2/en
Expired 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

Abstract

PURPOSE:To detect signal discontinuance securely by making a level comparison between a timing signal component extracted from a photo PCM signal and fixed signal level, by detecting signal discontinuance judging from the existence of a comparison output, and then by making a decision on a shot noise signal. CONSTITUTION:A photo PCM signal is applied to photo PCM receiver 1 and the avalanche diode of receiver 1 outputs a PCM signal. To this receiver 1, timing signal extraction circuit 2 is connected and a timing component when the photo PCM signal is inputted is outputted by a timing signal of constant amplitude. This timing signal is detected by envelope detection circuit 3 to output a signal of a fixed level or more. Further, the output of this circuit 3 is applied to comparator 4 and compared there with a reference value of the fixed level and when it is higher than the fixed level, the detection signal is outputted to the output of low-pass filter 5. Judging from the existence of this detection signal, the discontinuance of the photo PCM signal is detected to prevent malfunction due to a shot noise, etc., so that the discontinuance of the PCM signal will accurately be detected.
JP54009025A 1979-01-29 1979-01-29 Optical PCM receiver signal disconnection detection circuit Expired JPS592212B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP54009025A JPS592212B2 (en) 1979-01-29 1979-01-29 Optical PCM receiver signal disconnection detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP54009025A JPS592212B2 (en) 1979-01-29 1979-01-29 Optical PCM receiver signal disconnection detection circuit

Publications (2)

Publication Number Publication Date
JPS55100760A true JPS55100760A (en) 1980-07-31
JPS592212B2 JPS592212B2 (en) 1984-01-17

Family

ID=11709107

Family Applications (1)

Application Number Title Priority Date Filing Date
JP54009025A Expired JPS592212B2 (en) 1979-01-29 1979-01-29 Optical PCM receiver signal disconnection detection circuit

Country Status (1)

Country Link
JP (1) JPS592212B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5130837A (en) * 1989-07-27 1992-07-14 Fujitsu Limited Optical repeater haivng means for preventing malfunction due to the presence of noise

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5968414U (en) * 1982-10-29 1984-05-09 シチズン時計株式会社 watch band structure

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5130837A (en) * 1989-07-27 1992-07-14 Fujitsu Limited Optical repeater haivng means for preventing malfunction due to the presence of noise

Also Published As

Publication number Publication date
JPS592212B2 (en) 1984-01-17

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