JPS56124104A - Secret sound recording and reproducing device - Google Patents

Secret sound recording and reproducing device

Info

Publication number
JPS56124104A
JPS56124104A JP2469780A JP2469780A JPS56124104A JP S56124104 A JPS56124104 A JP S56124104A JP 2469780 A JP2469780 A JP 2469780A JP 2469780 A JP2469780 A JP 2469780A JP S56124104 A JPS56124104 A JP S56124104A
Authority
JP
Japan
Prior art keywords
code
recording
reproducing
circuit
sound recording
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
JP2469780A
Other languages
Japanese (ja)
Inventor
Hideo Inoue
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.)
Teac Corp
Original Assignee
Teac 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 Teac Corp filed Critical Teac Corp
Priority to JP2469780A priority Critical patent/JPS56124104A/en
Publication of JPS56124104A publication Critical patent/JPS56124104A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G11B20/00731—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving a digital rights management system for enforcing a usage restriction
    • G11B20/00818—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving a digital rights management system for enforcing a usage restriction wherein the usage restriction limits the signal quality, e.g. by low-pass filtering of audio signals or by reducing the resolution of video signals
    • G11B20/00826—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving a digital rights management system for enforcing a usage restriction wherein the usage restriction limits the signal quality, e.g. by low-pass filtering of audio signals or by reducing the resolution of video signals wherein a spoiler signal is added to degrade the signal quality
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
    • G11B5/027—Analogue recording

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)

Abstract

PURPOSE:To improve secrecy, by modulating the amplitude of the sound signal to record it and by mixing and recording the code signal which the user sets arbitrarily. CONSTITUTION:Band limiting circuit 11, amplitude modulating circuit 12, and mixing circuit 18 are provided between sound recording input terminal 3 of magnetic recording and reproducing device 1 and input terminal 10 of secret sound recording and reproducing additional device 2, and code setting part 21 is connected to mixing circuit 18 through code signal generating circuit 19. While setting the user's private code by code setting equipment 22 of recording-side of code signal generating circuit 19, the sound recording input signal is supplied to sound recording input terminal 10 and is subjected to amplitude modulation and is mixed with this code and is input to recording head 5 and is recorded onto magnetic tape 6. Thus, the demodulation output is not obtained unless the same code as the code set at the recording time is set by code setting equipment 23 of reproducing-side at the reproducing time due to reproducing head 7, thereby improving secrecy.
JP2469780A 1980-02-29 1980-02-29 Secret sound recording and reproducing device Pending JPS56124104A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2469780A JPS56124104A (en) 1980-02-29 1980-02-29 Secret sound recording and reproducing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2469780A JPS56124104A (en) 1980-02-29 1980-02-29 Secret sound recording and reproducing device

Publications (1)

Publication Number Publication Date
JPS56124104A true JPS56124104A (en) 1981-09-29

Family

ID=12145357

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2469780A Pending JPS56124104A (en) 1980-02-29 1980-02-29 Secret sound recording and reproducing device

Country Status (1)

Country Link
JP (1) JPS56124104A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0338794A2 (en) * 1988-04-20 1989-10-25 THORN EMI plc Apparatus for marking a recorded signal
WO2004066295A1 (en) * 2003-01-22 2004-08-05 Darknoise Techonolgies Limited Digital content protection

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5132507B2 (en) * 1972-05-17 1976-09-13
JPS53136404A (en) * 1977-05-02 1978-11-29 Motorola Inc Digital audio protecting system and method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5132507B2 (en) * 1972-05-17 1976-09-13
JPS53136404A (en) * 1977-05-02 1978-11-29 Motorola Inc Digital audio protecting system and method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0338794A2 (en) * 1988-04-20 1989-10-25 THORN EMI plc Apparatus for marking a recorded signal
WO2004066295A1 (en) * 2003-01-22 2004-08-05 Darknoise Techonolgies Limited Digital content protection

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