FR2385283A1 - Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78) - Google Patents

Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78)

Info

Publication number
FR2385283A1
FR2385283A1 FR7807117A FR7807117A FR2385283A1 FR 2385283 A1 FR2385283 A1 FR 2385283A1 FR 7807117 A FR7807117 A FR 7807117A FR 7807117 A FR7807117 A FR 7807117A FR 2385283 A1 FR2385283 A1 FR 2385283A1
Authority
FR
France
Prior art keywords
analogue signal
derives
stored value
recognition circuit
signal
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.)
Withdrawn
Application number
FR7807117A
Other languages
French (fr)
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of FR2385283A1 publication Critical patent/FR2385283A1/en
Withdrawn legal-status Critical Current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
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/45—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling
    • H04Q1/457—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling with conversion of multifrequency signals into digital signals

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Dc Digital Transmission (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

A digital processing technique is employed in telecommunications arrangements to eliminate costly steep-slope filters previously necessary for the detection of multitone control signals in the presence of speech signals. The composite analogue signal (a) derived from the individual code tones is converted to a constant amplitude pulse train of which individual pulse lengths correspond to the interval between successive corssing points of the analogue signal. The digital signals so obtained (b) are compared with fixed predetermined digital signals corresponding to the n frequency combinations in the full code range. Since the pulse trains exhibit mirror symmetry of the beat interval, it is necessary only to carry out the comparison for half of this period.
FR7807117A 1977-03-23 1978-03-13 Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78) Withdrawn FR2385283A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2712831A DE2712831B2 (en) 1977-03-23 1977-03-23 Speech-protected, frequency-selective character receiver

Publications (1)

Publication Number Publication Date
FR2385283A1 true FR2385283A1 (en) 1978-10-20

Family

ID=6004476

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7807117A Withdrawn FR2385283A1 (en) 1977-03-23 1978-03-13 Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78)

Country Status (6)

Country Link
JP (1) JPS53117903A (en)
DE (1) DE2712831B2 (en)
FR (1) FR2385283A1 (en)
IT (1) IT1093892B (en)
NL (1) NL7803090A (en)
SE (1) SE7803253L (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0081294A2 (en) * 1981-11-06 1983-06-15 Electronics Corporation Of Israel Limited Tone detector

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD259987A3 (en) * 1986-07-07 1988-09-14 Rft Nachrichtenelektronik Albe METHOD AND ARRANGEMENT FOR LANGUAGE PROTECTION IN MFC-TASTWAHLMPFAENGERN
DD266253A3 (en) * 1987-06-22 1989-03-29 Leipzig Rft Nachrichtenelekt UNIVERSAL DIGITAL MFC RECEPTIONER

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
EXBK/77 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0081294A2 (en) * 1981-11-06 1983-06-15 Electronics Corporation Of Israel Limited Tone detector
EP0081294A3 (en) * 1981-11-06 1984-05-16 Electronics Corporation Of Israel Limited Tone detector

Also Published As

Publication number Publication date
DE2712831A1 (en) 1978-10-05
NL7803090A (en) 1978-09-26
IT1093892B (en) 1985-07-26
JPS53117903A (en) 1978-10-14
DE2712831C3 (en) 1980-09-25
DE2712831B2 (en) 1980-01-24
IT7821481A0 (en) 1978-03-22
SE7803253L (en) 1978-09-24

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Legal Events

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