Apparatus and method for protecting the unauthorized duplication of a signal
First Claim
1. An apparatus for transmitting a signal, comprising:
- code generating means for generating a code;
additional information signal producing means for producing a high level narrow band additional information signal;
processing means for processing said high level narrow band additional information signal using said code to produce a low level wide band additional information signal;
first signal superimposing means for superimposing said high level narrow band additional information signal on said signal;
second signal superimposing means for superimposing said low level wide band additional information signal on said signal having said high level narrow band additional information signal superimposed thereon; and
transmitting means for transmitting an output from said second signal superimposing means.
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Accused Products
Abstract
An additional information produced by an additional information signal producing curcuit is spectrum-spread by a spectrum spreading code generated on the basis of the timing of the synchronous signal of digital video signal and is then added to the digital video signal by means of a signal adder. The digital video signal to which the spectrum spread additional information signal is added is then written into a recording medium by a signal writing device. Thereby, the additional information signal can be added to the video signal under the condition that the reproducing quality of the video signal is never deteriorated and alteration and deletion are impossible and moreover the additional information signal can be detected for use as required from the video signal.
12 Citations
10 Claims
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1. An apparatus for transmitting a signal, comprising:
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code generating means for generating a code;
additional information signal producing means for producing a high level narrow band additional information signal;
processing means for processing said high level narrow band additional information signal using said code to produce a low level wide band additional information signal;
first signal superimposing means for superimposing said high level narrow band additional information signal on said signal;
second signal superimposing means for superimposing said low level wide band additional information signal on said signal having said high level narrow band additional information signal superimposed thereon; and
transmitting means for transmitting an output from said second signal superimposing means. - View Dependent Claims (2, 3, 4, 5)
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6. A method for transmitting a signal, comprising the steps of:
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generating a code;
producing a high level narrow band additional information signal;
processing said high level narrow band additional information signal using said code to produce a low level wide band additional information signal;
superimposing said high level narrow band additional information signal on said signal;
superimposing said low level wide band additional information signal on said signal having said high level narrow band additional information signal superimposed thereon; and
transmitting an output from said step of superimposing said low level wide ban additional information signal. - View Dependent Claims (7, 8, 9, 10)
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Specification