WO2002023846A3 - Dial tone detector - Google Patents

Dial tone detector Download PDF

Info

Publication number
WO2002023846A3
WO2002023846A3 PCT/FR2001/002811 FR0102811W WO0223846A3 WO 2002023846 A3 WO2002023846 A3 WO 2002023846A3 FR 0102811 W FR0102811 W FR 0102811W WO 0223846 A3 WO0223846 A3 WO 0223846A3
Authority
WO
WIPO (PCT)
Prior art keywords
dial tone
tone detector
frequency
communications
fref
Prior art date
Application number
PCT/FR2001/002811
Other languages
French (fr)
Other versions
WO2002023846A2 (en
Inventor
Alain Chianale
Brigitte Belhi
Original Assignee
St Microelectronics Sa
Alain Chianale
Brigitte Belhi
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 St Microelectronics Sa, Alain Chianale, Brigitte Belhi filed Critical St Microelectronics Sa
Publication of WO2002023846A2 publication Critical patent/WO2002023846A2/en
Publication of WO2002023846A3 publication Critical patent/WO2002023846A3/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/30—Systems using multi-frequency codes wherein each code element is represented by a combination of frequencies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H04L27/06—Demodulator circuits; Receiver circuits

Abstract

The invention concerns a dial tone detector. Said dial tone detector comprises a synchronous filtering digital circuit for comparing the frequency of a dial tone with a reference frequency (Fref). The invention is applicable in the field of telephone communications and communications carried out via a modem.
PCT/FR2001/002811 2000-09-12 2001-09-11 Dial tone detector WO2002023846A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0011582A FR2814023B1 (en) 2000-09-12 2000-09-12 TONE DETECTOR
FR00/11582 2000-09-12

Publications (2)

Publication Number Publication Date
WO2002023846A2 WO2002023846A2 (en) 2002-03-21
WO2002023846A3 true WO2002023846A3 (en) 2002-05-10

Family

ID=8854189

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FR2001/002811 WO2002023846A2 (en) 2000-09-12 2001-09-11 Dial tone detector

Country Status (2)

Country Link
FR (1) FR2814023B1 (en)
WO (1) WO2002023846A2 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3675129A (en) * 1970-05-13 1972-07-04 Collins Radio Co Differentially coherent phase shift keyed digital demodulating apparatus
US4291269A (en) * 1979-06-28 1981-09-22 Rca Corporation System and method for frequency discrimination
US5007069A (en) * 1987-11-13 1991-04-09 Talkie Tooter Inc. Decoding of signals using cophase and differentiating signal detection
JPH10136042A (en) * 1996-11-01 1998-05-22 Hitachi Denshi Ltd Orthogonal demodulator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3675129A (en) * 1970-05-13 1972-07-04 Collins Radio Co Differentially coherent phase shift keyed digital demodulating apparatus
US4291269A (en) * 1979-06-28 1981-09-22 Rca Corporation System and method for frequency discrimination
US5007069A (en) * 1987-11-13 1991-04-09 Talkie Tooter Inc. Decoding of signals using cophase and differentiating signal detection
JPH10136042A (en) * 1996-11-01 1998-05-22 Hitachi Denshi Ltd Orthogonal demodulator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 1998, no. 10 31 August 1998 (1998-08-31) *

Also Published As

Publication number Publication date
FR2814023B1 (en) 2003-01-31
FR2814023A1 (en) 2002-03-15
WO2002023846A2 (en) 2002-03-21

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