JPS5534508A - Multi-frequency signal receiver - Google Patents

Multi-frequency signal receiver

Info

Publication number
JPS5534508A
JPS5534508A JP10621778A JP10621778A JPS5534508A JP S5534508 A JPS5534508 A JP S5534508A JP 10621778 A JP10621778 A JP 10621778A JP 10621778 A JP10621778 A JP 10621778A JP S5534508 A JPS5534508 A JP S5534508A
Authority
JP
Japan
Prior art keywords
output
dft
threshold level
receiver
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.)
Pending
Application number
JP10621778A
Other languages
Japanese (ja)
Inventor
Kazuto Hirose
Mitsuyoshi Hashida
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP10621778A priority Critical patent/JPS5534508A/en
Publication of JPS5534508A publication Critical patent/JPS5534508A/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

Abstract

PURPOSE:To obtain an economical logic circuit of the receiver which prevents the malfunction caused by the noise by shortening the action recovery time for the signal detection and making insensitive the recovery due to the signal short break after detection for the digital multi-frequency signal receiver using the discrete Fourier conversion. CONSTITUTION:Block A is the arithmetic part of tone spectrum intensity DFT, and the output logic part is shown by C. The output given from arithmetic output DFT is supplied to comparator 14 via PCM to be compared with the threshold level stored into register 15. And the output exceeding the threshold level is latched by shift register 23 in the form of logic 1. Receiver output SP is calculated through accumulators (30, 31) comprising the recovery time, and latch gate 29 is opened to FF1 when the signal specturm exists to shorten the recovery time. The threshold level set to register 33 is selected to secure the insensitivity for the short break. As the gate control is given to the reception information output with the SP value of the sum of DFT (omeganu) against the noise, the insensitivity is secured for the signals outside the band.
JP10621778A 1978-09-01 1978-09-01 Multi-frequency signal receiver Pending JPS5534508A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10621778A JPS5534508A (en) 1978-09-01 1978-09-01 Multi-frequency signal receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10621778A JPS5534508A (en) 1978-09-01 1978-09-01 Multi-frequency signal receiver

Publications (1)

Publication Number Publication Date
JPS5534508A true JPS5534508A (en) 1980-03-11

Family

ID=14427972

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10621778A Pending JPS5534508A (en) 1978-09-01 1978-09-01 Multi-frequency signal receiver

Country Status (1)

Country Link
JP (1) JPS5534508A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58205359A (en) * 1982-05-25 1983-11-30 Fujitsu Ltd Digital multi-frequency receiving system
JPS59125188A (en) * 1982-12-30 1984-07-19 Fujitsu Ltd Receiving system of digital multi-frequency signal
JPS6471292A (en) * 1987-08-14 1989-03-16 Mitel Corp Dial tone detector

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58205359A (en) * 1982-05-25 1983-11-30 Fujitsu Ltd Digital multi-frequency receiving system
JPS59125188A (en) * 1982-12-30 1984-07-19 Fujitsu Ltd Receiving system of digital multi-frequency signal
JPS6320076B2 (en) * 1982-12-30 1988-04-26 Fujitsu Ltd
JPS6471292A (en) * 1987-08-14 1989-03-16 Mitel Corp Dial tone detector

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