APPARATUS AND METHODS FOR INCLUDING CODES IN AUDIO SIGNALS AND DECODING

摘要

Apparatus and methods for including a code (68) having at least one code fre quency component in an audio signal (60) are provided. The abilities of various frequency components in the audio signal to mask th e code frequency component to human hearing are evaluate d (64), and based on these evaluations an amplitude (76) is assigned to the co de frequency component. Methods and apparatus for detect ing a code in an encoded audio signal are also provided. A code frequency compon ent in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio freq uencies including the frequency of the code component.