JPS5495107A - Push-button dial receiving system - Google Patents

Push-button dial receiving system

Info

Publication number
JPS5495107A
JPS5495107A JP187978A JP187978A JPS5495107A JP S5495107 A JPS5495107 A JP S5495107A JP 187978 A JP187978 A JP 187978A JP 187978 A JP187978 A JP 187978A JP S5495107 A JPS5495107 A JP S5495107A
Authority
JP
Japan
Prior art keywords
output
level
signals
input
push
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
JP187978A
Other languages
Japanese (ja)
Inventor
Katsumasa Ono
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 JP187978A priority Critical patent/JPS5495107A/en
Publication of JPS5495107A publication Critical patent/JPS5495107A/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

Abstract

PURPOSE:To make a circuit simple and small-size and improve performance by varying the threshold level of a limiter circuit according to the input signal level. CONSTITUTION:The output of an output timer which is operated by recognizing effective signals by a receiver is differentiated by differenciating circuit 28, and gates 26 and 26' are opened in a short time by the differenciated pulse at the rise of the output, and the level of input signals is checked by bistable circuits 27 and 27'. Then, on a basis of the output of circuits 17 and 27', the threshold level of variable threshold limiters 29 and 29' is made higher and lower in case of the input level over a normal value and below a normal value respectively, thereby preventing the malfunction dependent upon false signals.
JP187978A 1978-01-13 1978-01-13 Push-button dial receiving system Pending JPS5495107A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP187978A JPS5495107A (en) 1978-01-13 1978-01-13 Push-button dial receiving system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP187978A JPS5495107A (en) 1978-01-13 1978-01-13 Push-button dial receiving system

Publications (1)

Publication Number Publication Date
JPS5495107A true JPS5495107A (en) 1979-07-27

Family

ID=11513838

Family Applications (1)

Application Number Title Priority Date Filing Date
JP187978A Pending JPS5495107A (en) 1978-01-13 1978-01-13 Push-button dial receiving system

Country Status (1)

Country Link
JP (1) JPS5495107A (en)

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