Apparatus and method for generating binaural beat from stereo audio signal
An apparatus and method for generating a binaural beat for brainwave induction is provided. Upon receipt of a stereo audio signal, a decorrelator extracts a common component existing in common in both channels of the stereo audio signal, and outputs the remaining stereo components except for the extracted common component. A frequency shifter generates a common component in which the binaural beat is included, by shifting a frequency of the extracted common component. First and second mixers mix the common component in which the binaural beat is included, with the remaining stereo components.
1. An apparatus for generating a binaural beat, the apparatus comprising:
a decorrelator for, upon receipt of a stereo audio signal, extracting a common component existing in both channels of the stereo audio signal and outputting stereo components except for the extracted common component;
a frequency shifter for generating a common component that includes the binaural beat by shifting a frequency of the extracted common component; and
first and second mixers for mixing the common component that includes the binaural beat with the remaining stereo components.
2. The apparatus of claim 1 , further comprising:
a beat detector for detecting a tempo of a monaural beat of the stereo audio signal; and
first and second variable modifiers for adjusting strength of the common component that includes the binaural beat according to the detected tempo of the monaural beat, at both channels of the stereo audio signal.
3. The apparatus of claim 2 , wherein the first and second variable modifiers adjust strength of the common component that includes the binaural beat by changing a weight α according to the tempo of the monaural beat according to:
H ( z )=1+α z −1
where α corresponds to the tempo of the monaural beat, and z is a frequency.
4. The apparatus of claim 3 , wherein a value of α increases as the monaural beat becomes faster.
5. A method for generating a binaural beat, the method comprising:
upon receipt of a stereo audio signal, extracting a common component existing in both channels of the stereo audio signal and outputting stereo components except for the extracted common component;
generating a common component that includes the binaural beat by shifting a frequency of the extracted common component; and
mixing the common component that includes the binaural beat with the remaining stereo components.
6. The method of claim 5 , wherein generating a common component that includes the binaural beat further comprises:
detecting a tempo of a monaural beat of the received stereo audio signal; and
adjusting strength of the common component that includes the binaural beat according to the detected tempo of the monaural beat, at both channels of the stereo audio signal.
7. The method of claim 6 , wherein adjusting strength of the common component that includes the binaural beat further comprises:
adjusting strength of the common component that includes the binaural beat by changing a weight α according to the tempo of the monaural beat according to:
H ( z )=1+α z −1
where α corresponds to the tempo of the monaural beat, and z is a frequency.
8. The method of claim 7 , wherein a value of α increases as the monaural beat becomes faster.