BE899445A - Circuit de transmission pour appareil telephonique dtmf. - Google Patents

Circuit de transmission pour appareil telephonique dtmf.

Info

Publication number
BE899445A
BE899445A BE0/212784A BE212784A BE899445A BE 899445 A BE899445 A BE 899445A BE 0/212784 A BE0/212784 A BE 0/212784A BE 212784 A BE212784 A BE 212784A BE 899445 A BE899445 A BE 899445A
Authority
BE
Belgium
Prior art keywords
transmission circuit
telephone apparatus
tones
dtmf telephone
amplitude
Prior art date
Application number
BE0/212784A
Other languages
English (en)
Original Assignee
Philips Nv
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 Philips Nv filed Critical Philips Nv
Publication of BE899445A publication Critical patent/BE899445A/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/50—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies
    • H04M1/505—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies signals generated in digital form

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Telephone Function (AREA)
  • Analogue/Digital Conversion (AREA)

Abstract

Le filtre de tonalité de deuxième ordre, indispensable pour ce circuit de transmission est formé du fait que durant la procédure de sélection de numéro, le filtre de signal vocal (12) est branché en série avec un filtre de tonalité de premier ordre (10) à l'aide d'un commutateur (11). L'affaiblissement provoqué de la sorte dans le groupe II des tonalités de numérotation à fréquences élevées est compensé par l'augmentation de l'amplitude des tonalités de numérotation de ce groupe et par un accroissement supplémentaire de l'amplitude pour les tonalités ayant les deux fréquences les plus élevées dans le sous-groupe II (2).
BE0/212784A 1983-04-19 1984-04-17 Circuit de transmission pour appareil telephonique dtmf. BE899445A (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL8301366A NL8301366A (nl) 1983-04-19 1983-04-19 Transmissieschakeling voor een dtmf-telefoontoestel.

Publications (1)

Publication Number Publication Date
BE899445A true BE899445A (fr) 1984-10-17

Family

ID=19841727

Family Applications (1)

Application Number Title Priority Date Filing Date
BE0/212784A BE899445A (fr) 1983-04-19 1984-04-17 Circuit de transmission pour appareil telephonique dtmf.

Country Status (9)

Country Link
US (1) US4585909A (fr)
EP (1) EP0122680B1 (fr)
JP (1) JPS59202758A (fr)
BE (1) BE899445A (fr)
CA (1) CA1210540A (fr)
DE (1) DE3462209D1 (fr)
FR (1) FR2544938B1 (fr)
IT (1) IT1176066B (fr)
NL (1) NL8301366A (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0644781B2 (ja) * 1985-07-19 1994-06-08 株式会社日立製作所 デイジタルト−ン発生回路
JPH0236652A (ja) * 1988-07-27 1990-02-06 Sankyo Seiki Mfg Co Ltd オートダイヤル装置
AU622744B2 (en) * 1989-02-02 1992-04-16 Alcatel Australia Limited Dialler chip mode signal
US5907597A (en) * 1994-08-05 1999-05-25 Smart Tone Authentication, Inc. Method and system for the secure communication of data

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL160687C (nl) * 1972-06-10 1979-11-15 Philips Nv Toongenerator voor het opwekken van gekozen frequenties.
US3838348A (en) * 1973-06-25 1974-09-24 Bell Telephone Labor Inc Digital multifrequency signal generator
FR2368843A1 (fr) * 1976-10-22 1978-05-19 Constr Telephoniques Emetteur de signaux multifrequences

Also Published As

Publication number Publication date
IT1176066B (it) 1987-08-12
CA1210540A (fr) 1986-08-26
EP0122680B1 (fr) 1987-01-21
JPS59202758A (ja) 1984-11-16
FR2544938A1 (fr) 1984-10-26
JPH0351342B2 (fr) 1991-08-06
EP0122680A1 (fr) 1984-10-24
US4585909A (en) 1986-04-29
IT8420561A1 (it) 1985-10-16
IT8420561A0 (it) 1984-04-16
NL8301366A (nl) 1984-11-16
FR2544938B1 (fr) 1986-01-24
DE3462209D1 (en) 1987-02-26

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Legal Events

Date Code Title Description
RE Patent lapsed

Owner name: N.V. PHILIPS' GLOEILAMPENFABRIEKEN

Effective date: 19920430