| 摘要 |
<p>An inputted music signal and an advertisement voice signal are combined by a synthesizing section and a synthesized signal is encoded by a first encoding section. The advertisement voice signal is encoded and encrypted by a second encoding section and combined, by a code sequence synthesizing section, with the output from the first encoding section. Only the music signal combined with the advertisement voice signal is reproduced from the code sequence synthesized signal when encryption key information is not available but only the music signal can be reproduced by decoding the encrypted signal and thereby canceling the advertisement voice signal component in the synthesized signal. An information signal can be reproduced in an incomplete state (extra signals are added) even if encryption key information is not provided, and it can be reproduced in a complete state when the key information is available.</p> |
