JPS5632847A - Channel monitoring circuit - Google Patents

Channel monitoring circuit

Info

Publication number
JPS5632847A
JPS5632847A JP10893379A JP10893379A JPS5632847A JP S5632847 A JPS5632847 A JP S5632847A JP 10893379 A JP10893379 A JP 10893379A JP 10893379 A JP10893379 A JP 10893379A JP S5632847 A JPS5632847 A JP S5632847A
Authority
JP
Japan
Prior art keywords
signal
threshold level
counter
inputted
certain time
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
JP10893379A
Other languages
Japanese (ja)
Inventor
Kunihiko Niwa
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 JP10893379A priority Critical patent/JPS5632847A/en
Publication of JPS5632847A publication Critical patent/JPS5632847A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector

Abstract

PURPOSE:To send out an alarm by judging that when a demodulated signal exceeds a predetermined threshold level continuously for more than a certain time, a channel becomes abnormal, by monitoring over whether the demodulated signal exceeds the threshold level continuously for more than the certain time by comparing the demodulated signal to the threshold level at a reception side. CONSTITUTION:Demodulated signal (a) is compared with positive threshold level +Vth and negative threshold level -Vth by voltage comparators 304 and 306 to generate logical outputs 305 and 307. Logical outputs 305 and 307 are inputted to NOR gate 308 to generate signal 309, which is inputted to counter 310 as a reset signal. To counter 310, clock signal 311 whose repetitive frequency is previously known is inputted and carry signal 312 is outputted when the counter is placed in the full-count state, but when reset signal 309 increases in level to ''H'' in process of counting, the counter is reset and restarts counting. Therefore, if the carry signal is outputted, the reset signal is not held at ''H'' for more than a certain time, which is considered to be abnormality.
JP10893379A 1979-08-27 1979-08-27 Channel monitoring circuit Pending JPS5632847A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10893379A JPS5632847A (en) 1979-08-27 1979-08-27 Channel monitoring circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10893379A JPS5632847A (en) 1979-08-27 1979-08-27 Channel monitoring circuit

Publications (1)

Publication Number Publication Date
JPS5632847A true JPS5632847A (en) 1981-04-02

Family

ID=14497328

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10893379A Pending JPS5632847A (en) 1979-08-27 1979-08-27 Channel monitoring circuit

Country Status (1)

Country Link
JP (1) JPS5632847A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0144839A2 (en) * 1983-11-18 1985-06-19 Nec Corporation Squelch signal generator capable of generating a squelch signal with a high reliability

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0144839A2 (en) * 1983-11-18 1985-06-19 Nec Corporation Squelch signal generator capable of generating a squelch signal with a high reliability

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