JPS5564464A - Signal receiver - Google Patents

Signal receiver

Info

Publication number
JPS5564464A
JPS5564464A JP13789278A JP13789278A JPS5564464A JP S5564464 A JPS5564464 A JP S5564464A JP 13789278 A JP13789278 A JP 13789278A JP 13789278 A JP13789278 A JP 13789278A JP S5564464 A JPS5564464 A JP S5564464A
Authority
JP
Japan
Prior art keywords
maximum value
level
detected
circuits
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.)
Granted
Application number
JP13789278A
Other languages
Japanese (ja)
Other versions
JPS5831140B2 (en
Inventor
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 JP53137892A priority Critical patent/JPS5831140B2/en
Publication of JPS5564464A publication Critical patent/JPS5564464A/en
Publication of JPS5831140B2 publication Critical patent/JPS5831140B2/en
Expired 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
    • H04Q1/46—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

PURPOSE:To attain echo protection of a multi-frequency signal receiver by a maximum value detection circuit which detects the maximum value of an input signal and a variable threshold circuit which varies the detection level of a limiter circuit in accordance with an output level. CONSTITUTION:Branching filter 2 separates an input multi-frequency signal into one wave each in higher and lower groups, which are applied to limiter circuits 3' and 3'' and maximum value detection circuits 7' and 7''. The maximum value of a one-wave component is inputted to following variable threshold circuits 8' and 8'' and compared there with minimum level VF to be received to make a check on whether it is a level to be detected; when it is the level to be detected, a threshold level damped from the previously-detected maximum value as much as required is applied to detection level terminal 9 of limitters 3' and 3'' and when not, VF is applied. If an echo component arrivers, the discharge time constant of the maximum value detection circuit is adequately set for prevention.
JP53137892A 1978-11-10 1978-11-10 signal receiver Expired JPS5831140B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP53137892A JPS5831140B2 (en) 1978-11-10 1978-11-10 signal receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP53137892A JPS5831140B2 (en) 1978-11-10 1978-11-10 signal receiver

Publications (2)

Publication Number Publication Date
JPS5564464A true JPS5564464A (en) 1980-05-15
JPS5831140B2 JPS5831140B2 (en) 1983-07-04

Family

ID=15209108

Family Applications (1)

Application Number Title Priority Date Filing Date
JP53137892A Expired JPS5831140B2 (en) 1978-11-10 1978-11-10 signal receiver

Country Status (1)

Country Link
JP (1) JPS5831140B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03171994A (en) * 1989-11-30 1991-07-25 Hitachi Ltd Push-button dial signal receiving system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0428768Y2 (en) * 1985-03-26 1992-07-13
JPS61160937U (en) * 1985-03-26 1986-10-06

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52107708A (en) * 1976-03-03 1977-09-09 Northern Telecom Ltd Method and device for translating multiple frequency signal
JPS5471512A (en) * 1977-11-17 1979-06-08 Nec Corp Receiver for multi-frequency signal

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52107708A (en) * 1976-03-03 1977-09-09 Northern Telecom Ltd Method and device for translating multiple frequency signal
JPS5471512A (en) * 1977-11-17 1979-06-08 Nec Corp Receiver for multi-frequency signal

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03171994A (en) * 1989-11-30 1991-07-25 Hitachi Ltd Push-button dial signal receiving system

Also Published As

Publication number Publication date
JPS5831140B2 (en) 1983-07-04

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