JPS5795791A - Multi-frequency signal detector - Google Patents

Multi-frequency signal detector

Info

Publication number
JPS5795791A
JPS5795791A JP17155980A JP17155980A JPS5795791A JP S5795791 A JPS5795791 A JP S5795791A JP 17155980 A JP17155980 A JP 17155980A JP 17155980 A JP17155980 A JP 17155980A JP S5795791 A JPS5795791 A JP S5795791A
Authority
JP
Japan
Prior art keywords
circuits
output
frequency signal
terminal
given
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
JP17155980A
Other languages
Japanese (ja)
Inventor
Hirotsugu Ishikawa
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 JP17155980A priority Critical patent/JPS5795791A/en
Publication of JPS5795791A publication Critical patent/JPS5795791A/en
Pending 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
    • H04Q1/453—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling in which m-out-of-n signalling frequencies are transmitted

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)

Abstract

PURPOSE:To prevent the titled device from generation of an output even with reception of consecutive noise, by constituting a comparison circuit with one comparison circuit having a specified level of threshold and the other comparison circuit making a picked up output of frequency of a multi-frequency signal as the threshold value. CONSTITUTION:Each frequency component of a multi-frequency signal inputted to a terminal 10 is picked up at a low group filter 21 and a high group filter 22 and it is rectified at rectifying circuits 31 and 32. The output of the circuits 31 and 32 is applied to comparison circuits 41-44. The circuits 41 and 44 cause an output when the output of the circuits 31 and 32 is greater than the reference voltage Vs. On the other hand, a full band signal is given to the input of a rectifying circuit 33 via an attenuator 23. If white noise over the entire band is incoming consecutively, an output is obtained at the circuits 31-33, high threshold value is given to the circuits 42 and 43 and no output is obtained from the circuits 42 and 43. When a signal given to the terminal 10 is a normal multi-frequency signal, an output is obtained from the circuits 41-43 and when this state continues for a specified time or more, an output is transmitted to a terminal 80.
JP17155980A 1980-12-05 1980-12-05 Multi-frequency signal detector Pending JPS5795791A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17155980A JPS5795791A (en) 1980-12-05 1980-12-05 Multi-frequency signal detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17155980A JPS5795791A (en) 1980-12-05 1980-12-05 Multi-frequency signal detector

Publications (1)

Publication Number Publication Date
JPS5795791A true JPS5795791A (en) 1982-06-14

Family

ID=15925374

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17155980A Pending JPS5795791A (en) 1980-12-05 1980-12-05 Multi-frequency signal detector

Country Status (1)

Country Link
JP (1) JPS5795791A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4623207A (en) * 1984-06-26 1986-11-18 Oki Densen Kabushiki Kaisha Printed circuit board connector

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4623207A (en) * 1984-06-26 1986-11-18 Oki Densen Kabushiki Kaisha Printed circuit board connector

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