JPS55100774A - Tone detection circuit - Google Patents

Tone detection circuit

Info

Publication number
JPS55100774A
JPS55100774A JP896379A JP896379A JPS55100774A JP S55100774 A JPS55100774 A JP S55100774A JP 896379 A JP896379 A JP 896379A JP 896379 A JP896379 A JP 896379A JP S55100774 A JPS55100774 A JP S55100774A
Authority
JP
Japan
Prior art keywords
inputted
tone detection
shift register
sampled data
detection circuit
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
JP896379A
Other languages
Japanese (ja)
Inventor
Yoshitake Matsuo
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.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co 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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP896379A priority Critical patent/JPS55100774A/en
Publication of JPS55100774A publication Critical patent/JPS55100774A/en
Pending legal-status Critical Current

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

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

PURPOSE:To simplify a tone detection circuit by digitizing, by using ROM for a communication system using a tone signal. CONSTITUTION:Tone signal 1 is inputted to comparator 2 to obtain a binary zero- cross wave. This is sampled by sampling clock 4 from sampling clock generator 9 and its output is inputted to shift register 5. The length of this shift register 5 is the number of samples for finding power. Parallel output 6 of respective bits of shift register 5, namely, a series of sampled data is inputted to the address input terminal of ROM7. Corresponding to all combinations of sampled data serieses, ROM7 is stored with data of ''1'' and ''0'' showing the existence of tone detection and every time one series of sampled data is inputted, corresponding tone detection output 8 is sent out.
JP896379A 1979-01-29 1979-01-29 Tone detection circuit Pending JPS55100774A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP896379A JPS55100774A (en) 1979-01-29 1979-01-29 Tone detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP896379A JPS55100774A (en) 1979-01-29 1979-01-29 Tone detection circuit

Publications (1)

Publication Number Publication Date
JPS55100774A true JPS55100774A (en) 1980-07-31

Family

ID=11707320

Family Applications (1)

Application Number Title Priority Date Filing Date
JP896379A Pending JPS55100774A (en) 1979-01-29 1979-01-29 Tone detection circuit

Country Status (1)

Country Link
JP (1) JPS55100774A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04120840A (en) * 1990-09-12 1992-04-21 Nec Corp Tone signal detecting circuit
WO1993015580A1 (en) * 1992-01-29 1993-08-05 Fujitsu Limited Circuit for detecting object signal from input signal
US5406975A (en) * 1993-03-12 1995-04-18 Aisan Kogyo Kabushiki Kaisha Flow rate control valve

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04120840A (en) * 1990-09-12 1992-04-21 Nec Corp Tone signal detecting circuit
WO1993015580A1 (en) * 1992-01-29 1993-08-05 Fujitsu Limited Circuit for detecting object signal from input signal
US5471507A (en) * 1992-01-29 1995-11-28 Fujitsu Limited Circuit for detecting object signal from input signal
US5406975A (en) * 1993-03-12 1995-04-18 Aisan Kogyo Kabushiki Kaisha Flow rate control valve

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