JPS5571392A - Digital multi-frequency signal receiver - Google Patents

Digital multi-frequency signal receiver

Info

Publication number
JPS5571392A
JPS5571392A JP14494478A JP14494478A JPS5571392A JP S5571392 A JPS5571392 A JP S5571392A JP 14494478 A JP14494478 A JP 14494478A JP 14494478 A JP14494478 A JP 14494478A JP S5571392 A JPS5571392 A JP S5571392A
Authority
JP
Japan
Prior art keywords
discrete fourier
signals
continuity test
conversion operation
fourier conversion
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
JP14494478A
Other languages
Japanese (ja)
Inventor
Kensaku Fujii
Yoshimasa Kaneko
Tatsuro Miyoshi
Akira Fukui
Kojiro Sakurai
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.)
Fujitsu Ltd
Hitachi Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Oki Electric Industry Co Ltd
Original Assignee
Fujitsu Ltd
Hitachi Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Oki Electric Industry Co Ltd
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 Fujitsu Ltd, Hitachi Ltd, NEC Corp, Nippon Telegraph and Telephone Corp, Oki Electric Industry Co Ltd, Nippon Electric Co Ltd filed Critical Fujitsu Ltd
Priority to JP14494478A priority Critical patent/JPS5571392A/en
Publication of JPS5571392A publication Critical patent/JPS5571392A/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
    • H04Q1/457—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)

Abstract

PURPOSE:To prevent an unavailable time slot from being generated, by providing a discrete Fourier conversion operation unit for every detection frequency. CONSTITUTION:Since frequencies used for multi-frequency signals and continuity test signals are 700, 900, 1100, 1300, 1500 and 1700Hz, discrete Fourier conversion operation circuits 11-16 are provided for respective frequencies. Output values from circuits 11-16 are transferred to one decision circuit 20' to decide presence or absence of signals. Thus, the time slot of each discrete Fourier operation circuit is always available, and unavailable time slots are eliminated, and each discrete Fourier conversion operation circuit operates without distinguishing multi-frequency signals and continuity test signals from each other. Consequently, change in hardware is not required even if combination of the number of lines for multi-frequency signals and the number of lines for continuity test signals is changed.
JP14494478A 1978-11-25 1978-11-25 Digital multi-frequency signal receiver Pending JPS5571392A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14494478A JPS5571392A (en) 1978-11-25 1978-11-25 Digital multi-frequency signal receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14494478A JPS5571392A (en) 1978-11-25 1978-11-25 Digital multi-frequency signal receiver

Publications (1)

Publication Number Publication Date
JPS5571392A true JPS5571392A (en) 1980-05-29

Family

ID=15373808

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14494478A Pending JPS5571392A (en) 1978-11-25 1978-11-25 Digital multi-frequency signal receiver

Country Status (1)

Country Link
JP (1) JPS5571392A (en)

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