JPS57180274A - Television relay system - Google Patents

Television relay system

Info

Publication number
JPS57180274A
JPS57180274A JP6545581A JP6545581A JPS57180274A JP S57180274 A JPS57180274 A JP S57180274A JP 6545581 A JP6545581 A JP 6545581A JP 6545581 A JP6545581 A JP 6545581A JP S57180274 A JPS57180274 A JP S57180274A
Authority
JP
Japan
Prior art keywords
signal
receiver
failure
reception
alarm
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
JP6545581A
Other languages
Japanese (ja)
Inventor
Hiroshi Kawamoto
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.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co 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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP6545581A priority Critical patent/JPS57180274A/en
Publication of JPS57180274A publication Critical patent/JPS57180274A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/38—Transmitter circuitry for the transmission of television signals according to analogue transmission standards

Abstract

PURPOSE:To enable to discriminate instantly if any line is in failure, by giving an IF signal modulated with a specific frequency to an IF signal input terminal of transmission automatically, if reception is impossible at a relay point, and detecting the modulated frequency at the final receiving point. CONSTITUTION:A microwave received at an antenna 17 is converted into IF at a receiver 9 and IF-amplified. If the receiver 9 or the like is in failure and a reception detector 10 gives an alarm, the signal operates an IF switch 11 to change over an IF input 20 of an SHF transmitter 14 to an IF oscillator 12 and the signal is transmitted. The output of a receiver 15 at the final receiving point is provided with an alarm detector 16, and the presence/absence of the alarm signal in the reception signal is detected, allowing to instantly detect at which point the switch 11 is in operation and which line is in failure from the component.
JP6545581A 1981-04-30 1981-04-30 Television relay system Pending JPS57180274A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6545581A JPS57180274A (en) 1981-04-30 1981-04-30 Television relay system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6545581A JPS57180274A (en) 1981-04-30 1981-04-30 Television relay system

Publications (1)

Publication Number Publication Date
JPS57180274A true JPS57180274A (en) 1982-11-06

Family

ID=13287622

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6545581A Pending JPS57180274A (en) 1981-04-30 1981-04-30 Television relay system

Country Status (1)

Country Link
JP (1) JPS57180274A (en)

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