JPS57109440A - Transmission monitor system - Google Patents

Transmission monitor system

Info

Publication number
JPS57109440A
JPS57109440A JP55183889A JP18388980A JPS57109440A JP S57109440 A JPS57109440 A JP S57109440A JP 55183889 A JP55183889 A JP 55183889A JP 18388980 A JP18388980 A JP 18388980A JP S57109440 A JPS57109440 A JP S57109440A
Authority
JP
Japan
Prior art keywords
signal
taken out
harmonic
pass filter
band pass
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
JP55183889A
Other languages
Japanese (ja)
Inventor
Masafumi Tanaka
Hiroshi Izumikawa
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 Denshi KK
Original Assignee
Hitachi Denshi KK
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 Denshi KK filed Critical Hitachi Denshi KK
Priority to JP55183889A priority Critical patent/JPS57109440A/en
Publication of JPS57109440A publication Critical patent/JPS57109440A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/40—Monitoring; Testing of relay systems
    • H04B17/401—Monitoring; Testing of relay systems with selective localization
    • H04B17/402—Monitoring; Testing of relay systems with selective localization using different frequencies
    • H04B17/403—Monitoring; Testing of relay systems with selective localization using different frequencies generated by local oscillators

Abstract

PURPOSE:To monitor the qualiay of transmission at a remote modulating part with a simple circuit constitution, by taking out a harmonic signal from a frequency converting part. CONSTITUTION:A part of the transmission output signal is taken out by a directional coupler 14 and is mixed with the signal of a local oscillator 13 common to the main line by a harmonic mixer 16, and this second harmonic signal is taken out by a band pass filter 17. This modulated video signal is multiplexed on a coaxial cable 3 and is separated by a band pass filter 8 of a modulating part 1. The separated video signal is demodulated by a demodulator 7 and is taken out from a monitor output terminal 9.
JP55183889A 1980-12-26 1980-12-26 Transmission monitor system Pending JPS57109440A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP55183889A JPS57109440A (en) 1980-12-26 1980-12-26 Transmission monitor system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP55183889A JPS57109440A (en) 1980-12-26 1980-12-26 Transmission monitor system

Publications (1)

Publication Number Publication Date
JPS57109440A true JPS57109440A (en) 1982-07-07

Family

ID=16143580

Family Applications (1)

Application Number Title Priority Date Filing Date
JP55183889A Pending JPS57109440A (en) 1980-12-26 1980-12-26 Transmission monitor system

Country Status (1)

Country Link
JP (1) JPS57109440A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61170158A (en) * 1985-01-23 1986-07-31 Nec Corp Optical transmission supervisory device
US11287158B2 (en) 2017-11-21 2022-03-29 Noritz Corporation Heat exchanger and hot water apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61170158A (en) * 1985-01-23 1986-07-31 Nec Corp Optical transmission supervisory device
JPH0574970B2 (en) * 1985-01-23 1993-10-19 Nippon Electric Co
US11287158B2 (en) 2017-11-21 2022-03-29 Noritz Corporation Heat exchanger and hot water apparatus

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