JPS5799891A - Multifrequency signal receiver - Google Patents

Multifrequency signal receiver

Info

Publication number
JPS5799891A
JPS5799891A JP55175816A JP17581680A JPS5799891A JP S5799891 A JPS5799891 A JP S5799891A JP 55175816 A JP55175816 A JP 55175816A JP 17581680 A JP17581680 A JP 17581680A JP S5799891 A JPS5799891 A JP S5799891A
Authority
JP
Japan
Prior art keywords
circuit
output
selector
threshold value
value generating
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.)
Granted
Application number
JP55175816A
Other languages
Japanese (ja)
Other versions
JPH0139275B2 (en
Inventor
Ryujiro Muramatsu
Kazuto Hirose
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.)
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 JP55175816A priority Critical patent/JPS5799891A/en
Publication of JPS5799891A publication Critical patent/JPS5799891A/en
Publication of JPH0139275B2 publication Critical patent/JPH0139275B2/ja
Granted 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)
  • Complex Calculations (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

PURPOSE:To prevent malfunction due to momentary interruption of signal level and to quicken the restoration of device, by detecting spectrum of specific frequency when an output of discrete Fourier transformation operating circuit is a threshold value or more, selecting and comparing the 1st-3rd threshold values in accordance with the reception state. CONSTITUTION:A specific frequency spectrum is picked up from an input multifrequency signal at a discrete Fourier transformation operating section 22 and outputted at a prescribed period and inputted to the 3rd threshold value generating circuit 32 and a comparison circuit 29. The 3rd output lower by a given level from the maximum value of the output is outputted from the circuit 32 and added to an adder 35, the result is compared with the output of the 2nd threshold value generating circuit 31 and the result is added to a code bit storage circuit 34. The output of the circuit 34 controls the 1st selector 35 and selects the output of the circuit 32 or 31 in accordance with the plus or minus code and applied to the 2nd selector 36. The selector 36 is controlled with an output of a signal present circuit 37 taking the output of the circuit 29 as input, the output of the 1st threshold value generating circuit 30 or a selector 35 is selected and applied to the circuit 29.
JP55175816A 1980-12-15 1980-12-15 Multifrequency signal receiver Granted JPS5799891A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP55175816A JPS5799891A (en) 1980-12-15 1980-12-15 Multifrequency signal receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP55175816A JPS5799891A (en) 1980-12-15 1980-12-15 Multifrequency signal receiver

Publications (2)

Publication Number Publication Date
JPS5799891A true JPS5799891A (en) 1982-06-21
JPH0139275B2 JPH0139275B2 (en) 1989-08-18

Family

ID=16002724

Family Applications (1)

Application Number Title Priority Date Filing Date
JP55175816A Granted JPS5799891A (en) 1980-12-15 1980-12-15 Multifrequency signal receiver

Country Status (1)

Country Link
JP (1) JPS5799891A (en)

Also Published As

Publication number Publication date
JPH0139275B2 (en) 1989-08-18

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