| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a signal adding device and a signal removing device which can protect copyright by a noise signal, enable a user to purchase 2nd key information and enable a contents provider to protect contents of high sound quality from illegal copying. <P>SOLUTION: The signal adding device 101 for adding a signal to an input signal is provided with a delay means 102 for holding the signal added to the input signal for a prescribed time, a feature value extraction means 103 for extracting a prescribed feature value from an output signal outputted from the delay means 102, a noise signal source 104 for generating a noise signal on the basis of an output signal from the feature value extraction means 103 and key information, an amplifier 105 for multiplying the noise signal which is an output signal from the noise signal source 104 by a constant, and an adder 106 for adding the output signal of the amplifier 105 to the input signal and outputting the added signal. <P>COPYRIGHT: (C)2004,JPO |
