FR2260235A1 - Low frequency telephony pulse detector - detects test signal in synchronism with strong active signal presence - Google Patents

Low frequency telephony pulse detector - detects test signal in synchronism with strong active signal presence

Info

Publication number
FR2260235A1
FR2260235A1 FR7403795A FR7403795A FR2260235A1 FR 2260235 A1 FR2260235 A1 FR 2260235A1 FR 7403795 A FR7403795 A FR 7403795A FR 7403795 A FR7403795 A FR 7403795A FR 2260235 A1 FR2260235 A1 FR 2260235A1
Authority
FR
France
Prior art keywords
signal
synchronism
low frequency
test signal
pulse detector
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
FR7403795A
Other languages
French (fr)
Other versions
FR2260235B1 (en
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.)
Alcatel CIT SA
Original Assignee
Alcatel CIT SA
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 Alcatel CIT SA filed Critical Alcatel CIT SA
Priority to FR7403795A priority Critical patent/FR2260235A1/en
Publication of FR2260235A1 publication Critical patent/FR2260235A1/en
Application granted granted Critical
Publication of FR2260235B1 publication Critical patent/FR2260235B1/fr
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/24—Arrangements for supervision, monitoring or testing with provision for checking the normal operation

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Monitoring And Testing Of Exchanges (AREA)

Abstract

The circuit is used in telephony when line checking at 50Hz and 450Hz. The locally generated signal at high level is connected to a bridge rectifier (D4-7) and it provides the supply to a transistor detector stage (T5). The test signal after attenuation through line equipment is amplified and squared (T1, T2) and slaves a monstable multivibrator (T3, T4). This square-wave passes to the detector and if the stage is active (i.e. the high level signal is present) a diode and capacitor circuit (D2, C7) links it to an output transistor that provides an output signal and energises a light-emitting diode. This circuit protects against false readings caused by parasitic voltages by its system of coincidence detection.
FR7403795A 1974-02-05 1974-02-05 Low frequency telephony pulse detector - detects test signal in synchronism with strong active signal presence Granted FR2260235A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7403795A FR2260235A1 (en) 1974-02-05 1974-02-05 Low frequency telephony pulse detector - detects test signal in synchronism with strong active signal presence

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7403795A FR2260235A1 (en) 1974-02-05 1974-02-05 Low frequency telephony pulse detector - detects test signal in synchronism with strong active signal presence

Publications (2)

Publication Number Publication Date
FR2260235A1 true FR2260235A1 (en) 1975-08-29
FR2260235B1 FR2260235B1 (en) 1976-11-26

Family

ID=9134490

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7403795A Granted FR2260235A1 (en) 1974-02-05 1974-02-05 Low frequency telephony pulse detector - detects test signal in synchronism with strong active signal presence

Country Status (1)

Country Link
FR (1) FR2260235A1 (en)

Also Published As

Publication number Publication date
FR2260235B1 (en) 1976-11-26

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Legal Events

Date Code Title Description
ST Notification of lapse