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JPS6414771A - Unauthorized copy preventing system - Google Patents

Unauthorized copy preventing system

Info

Publication number
JPS6414771A
JPS6414771A JP17025087A JP17025087A JPS6414771A JP S6414771 A JPS6414771 A JP S6414771A JP 17025087 A JP17025087 A JP 17025087A JP 17025087 A JP17025087 A JP 17025087A JP S6414771 A JPS6414771 A JP S6414771A
Authority
JP
Japan
Prior art keywords
copy code
copy
adder
amplifier
calculator
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
JP17025087A
Other languages
Japanese (ja)
Other versions
JP2568562B2 (en
Inventor
Yutaka Kamikawa
Kenichi Takahashi
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co 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 Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP62170250A priority Critical patent/JP2568562B2/en
Publication of JPS6414771A publication Critical patent/JPS6414771A/en
Application granted granted Critical
Publication of JP2568562B2 publication Critical patent/JP2568562B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Landscapes

  • Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)

Abstract

PURPOSE:To obtain an unauthorized copy preventing system reducing the deterioration of sound quality by providing a delaying device, an amplifier and an adder as a copy code encoder and providing a normalizing self-correlation function calculator as a copy code detector. CONSTITUTION:The titled system is provided with the copy code encoder constituted of the delaying device 1, the amplifier 2 and the adder 3 and the copy code detector constituted of a low frequency component removing filter 7, the normalizing self-correlation function calculator 5, a maximum function value calculator 6, a mean function value calculator, and a level difference decider 8. An audio original signal is delayed by the delaying device 1 and amplified K times by the amplifier 2. Provided that K is a positive value <1. The amplified output is added to the audio original signal by the adder 3 and an audio signal with a copy code is outputted. Thus, the deterioration of sound quality can be reduced only by adding a slight echo to the audio signal with the copy code.
JP62170250A 1987-07-08 1987-07-08 Illegal copy prevention system Expired - Lifetime JP2568562B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62170250A JP2568562B2 (en) 1987-07-08 1987-07-08 Illegal copy prevention system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62170250A JP2568562B2 (en) 1987-07-08 1987-07-08 Illegal copy prevention system

Publications (2)

Publication Number Publication Date
JPS6414771A true JPS6414771A (en) 1989-01-18
JP2568562B2 JP2568562B2 (en) 1997-01-08

Family

ID=15901457

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62170250A Expired - Lifetime JP2568562B2 (en) 1987-07-08 1987-07-08 Illegal copy prevention system

Country Status (1)

Country Link
JP (1) JP2568562B2 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5963010A (en) * 1982-10-01 1984-04-10 Matsushita Electric Ind Co Ltd Sound reproducing device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5963010A (en) * 1982-10-01 1984-04-10 Matsushita Electric Ind Co Ltd Sound reproducing device

Also Published As

Publication number Publication date
JP2568562B2 (en) 1997-01-08

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