JPS5252507A - Frequency discriminator - Google Patents

Frequency discriminator

Info

Publication number
JPS5252507A
JPS5252507A JP12827975A JP12827975A JPS5252507A JP S5252507 A JPS5252507 A JP S5252507A JP 12827975 A JP12827975 A JP 12827975A JP 12827975 A JP12827975 A JP 12827975A JP S5252507 A JPS5252507 A JP S5252507A
Authority
JP
Japan
Prior art keywords
frequency discriminator
telephone
discrimination
controlled
sine wave
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
JP12827975A
Other languages
Japanese (ja)
Inventor
Kaoru Chiba
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 Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP12827975A priority Critical patent/JPS5252507A/en
Publication of JPS5252507A publication Critical patent/JPS5252507A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/64—Automatic arrangements for answering calls; Automatic arrangements for recording messages for absent subscribers; Arrangements for recording conversations
    • H04M1/65—Recording arrangements for recording a message from the calling party
    • H04M1/654—Telephone line monitoring circuits therefor, e.g. ring detectors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/82—Line monitoring circuits for call progress or status discrimination

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)

Abstract

PURPOSE:Through discrimination of aural signal and sine wave signal, automatic telephone answering device is controlled in order to stop recording when calling party cuts off telephone.
JP12827975A 1975-10-27 1975-10-27 Frequency discriminator Pending JPS5252507A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12827975A JPS5252507A (en) 1975-10-27 1975-10-27 Frequency discriminator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12827975A JPS5252507A (en) 1975-10-27 1975-10-27 Frequency discriminator

Publications (1)

Publication Number Publication Date
JPS5252507A true JPS5252507A (en) 1977-04-27

Family

ID=14980885

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12827975A Pending JPS5252507A (en) 1975-10-27 1975-10-27 Frequency discriminator

Country Status (1)

Country Link
JP (1) JPS5252507A (en)

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