| 摘要 |
An improved embedded signaling apparatus and method of embedding data into audio signals occurring at substantially zero decibel levels is disclosed. Embedding is accomplished at such low inaudible levels by modifying an embedded signaling encoder with a dither generator, dither adder and dither subtracter that generates, adds and subtracts dither signals, of equal magnitude, to audio signals at specified bit rates. Because the dither signal is used substantially within the encoder and is substantially canceled before final output, the dither signal provides an additional signal level, depth or dimension in the absence of audio data. Thus, whenever music or other audio data that will ultimately become audible reaches a very low decibel level, such as during periods of silence on a CD, the effectiveness of embedding data into such low level signals is not impaired. The embedded signaling encoder of the present invention can also be used for authentication purposes.
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