ES406799A1 - Signal generator - Google Patents

Signal generator

Info

Publication number
ES406799A1
ES406799A1 ES406799A ES406799A ES406799A1 ES 406799 A1 ES406799 A1 ES 406799A1 ES 406799 A ES406799 A ES 406799A ES 406799 A ES406799 A ES 406799A ES 406799 A1 ES406799 A1 ES 406799A1
Authority
ES
Spain
Prior art keywords
filter
series
signal generator
resistive elements
parallel configuration
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.)
Expired
Application number
ES406799A
Other languages
Spanish (es)
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.)
AT&T Corp
Original Assignee
Western Electric Co Inc
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 Western Electric Co Inc filed Critical Western Electric Co Inc
Publication of ES406799A1 publication Critical patent/ES406799A1/en
Expired 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
    • H04M1/26—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

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Push-Button Switches (AREA)
  • Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Electronic Switches (AREA)
  • Telephonic Communication Services (AREA)

Abstract

A key operated signal generator comprising a pair of interconnected transistor oscillators having twin-T notch-filter feedback networks in which one resistance in each filter is variable and consists of a plurality of resistive elements arranged in a series parallel configuration. The series parallel configuration is such that when a single button of the key is actuated, at least two resistive elements are connected in series in each filter and when two buttons are actuated simultaneously, at least one resistive element is connected in series with two or more parallel resistive elements in at least one filter.
ES406799A 1971-09-07 1972-09-07 Signal generator Expired ES406799A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17812671A 1971-09-07 1971-09-07

Publications (1)

Publication Number Publication Date
ES406799A1 true ES406799A1 (en) 1975-10-16

Family

ID=22651310

Family Applications (1)

Application Number Title Priority Date Filing Date
ES406799A Expired ES406799A1 (en) 1971-09-07 1972-09-07 Signal generator

Country Status (10)

Country Link
US (1) US3699477A (en)
JP (1) JPS5228522B2 (en)
BE (1) BE788462A (en)
CA (1) CA958083A (en)
DE (1) DE2243625C3 (en)
ES (1) ES406799A1 (en)
FR (1) FR2152669B1 (en)
GB (1) GB1411418A (en)
IT (1) IT965227B (en)
NL (1) NL7212067A (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7212510A (en) * 1972-09-15 1974-03-19
CA988175A (en) * 1974-06-14 1976-04-27 Michael C.J. Cowpland Tone generator
US4110568A (en) * 1976-10-08 1978-08-29 Gte Atea, S.A. Dual tone multifrequency generator
JPS5461804A (en) * 1977-10-26 1979-05-18 Mitsubishi Electric Corp Information transmitter
US6326853B1 (en) * 1999-08-26 2001-12-04 Cypress Semiconductor Corp Circuitry, architecture and method(s) for phase matching and/or reducing load capacitance, current and/or power consumption in an oscillator
US8605889B2 (en) 2011-11-18 2013-12-10 Edward D. REGAN Method and device for encoding characters and routing calls using expanded dual-tone multi-frequency (DTMF) encoding scheme

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3349350A (en) * 1964-12-04 1967-10-24 Otto E Rittenbach Frequency step filter
US3424870A (en) * 1965-09-14 1969-01-28 Bell Telephone Labor Inc Multifrequency signal generator for tone-dialed telephones

Also Published As

Publication number Publication date
GB1411418A (en) 1975-10-22
US3699477A (en) 1972-10-17
DE2243625B2 (en) 1974-08-29
JPS5228522B2 (en) 1977-07-27
IT965227B (en) 1974-01-31
JPS4837005A (en) 1973-05-31
DE2243625C3 (en) 1975-04-17
BE788462A (en) 1973-01-02
DE2243625A1 (en) 1973-03-15
FR2152669B1 (en) 1976-03-12
CA958083A (en) 1974-11-19
FR2152669A1 (en) 1973-04-27
NL7212067A (en) 1973-03-09

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