JPS57129554A - Privacy telephone set - Google Patents

Privacy telephone set

Info

Publication number
JPS57129554A
JPS57129554A JP1515281A JP1515281A JPS57129554A JP S57129554 A JPS57129554 A JP S57129554A JP 1515281 A JP1515281 A JP 1515281A JP 1515281 A JP1515281 A JP 1515281A JP S57129554 A JPS57129554 A JP S57129554A
Authority
JP
Japan
Prior art keywords
converter
telephone set
spectrum
privacy telephone
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
JP1515281A
Other languages
Japanese (ja)
Inventor
Katsumi Kobayashi
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.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone Corp
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 Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP1515281A priority Critical patent/JPS57129554A/en
Publication of JPS57129554A publication Critical patent/JPS57129554A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication
    • H04K1/04—Secret communication by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)

Abstract

PURPOSE:To realize the miniaturization of a privacy telephone set, by combining an A/D converter, a D/A converter, a digital multiplier and a gate circuit respectively and transmitting an aural signal after inverting its spectrum. CONSTITUTION:An aural signal a(t) given through an input terminal 11 is sampled at an A/D converter 21 by the clock given from a clock generator 22 and with a cycle T to be converted into a binary digital code train a(KT), where K is an integer. Then a spectrum inverting circuit 23 gives an operation of (-)K a(KT) to the train a(KT). The signal received an inversion of spectrum is converted into an analog signal through a D/A converter 24. In such a way, a privacy telephone set can be miniaturized to be suited to an IC.
JP1515281A 1981-02-04 1981-02-04 Privacy telephone set Pending JPS57129554A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1515281A JPS57129554A (en) 1981-02-04 1981-02-04 Privacy telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1515281A JPS57129554A (en) 1981-02-04 1981-02-04 Privacy telephone set

Publications (1)

Publication Number Publication Date
JPS57129554A true JPS57129554A (en) 1982-08-11

Family

ID=11880822

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1515281A Pending JPS57129554A (en) 1981-02-04 1981-02-04 Privacy telephone set

Country Status (1)

Country Link
JP (1) JPS57129554A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0295039A (en) * 1988-09-30 1990-04-05 Nec Corp Modulator for privacy communication

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS511385A (en) * 1973-10-30 1976-01-08 Wet Talc Ab
JPS5450263A (en) * 1977-09-28 1979-04-20 Mitsubishi Electric Corp Synchronous demodulator

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS511385A (en) * 1973-10-30 1976-01-08 Wet Talc Ab
JPS5450263A (en) * 1977-09-28 1979-04-20 Mitsubishi Electric Corp Synchronous demodulator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0295039A (en) * 1988-09-30 1990-04-05 Nec Corp Modulator for privacy communication

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