Audio adjustment method and associated audio adjustment device for active noise cancellation

1. An audio adjustment method for active noise cancellation, comprising:

obtaining multiple optimal noise cancellation responses of multiple frequencies, comprising:

for each frequency f k of the multiple frequencies:

broadcasting a single tone having said each frequency f k ;

generating M sets of filtering coefficients regarding said each frequency f k , wherein each set of filtering coefficients within the M sets of filtering coefficients comprises a combination of an amplitude and a phase, and the M sets of filtering coefficients are different from one another;

determining a m th set of filtering coefficients from the M sets of filtering coefficients to minimize energy corresponding to said each frequency f k , wherein the amplitude and the phase of the m th set of filtering coefficients represents an optimal noise cancellation response corresponding to said each frequency f k ; and

adjusting the single tone with the m th set of filtering coefficients to obtain an adjusted single tone corresponding to said each frequency f k ; and

determining a final set of active noise cancellation coefficients according to the multiple optimal noise cancellation responses of the multiple frequencies.

2. The audio adjustment method of claim 1 , wherein the step of adjusting the single tone with the m th set of filtering coefficients to obtain the adjusted single tone corresponding to said each frequency f k comprises:

utilizing an amplitude and a phase corresponding to the m th set of filtering coefficients to be a frequency response of said each frequency f k ; and

determining the adjusted single tone according to the frequency response of said each frequency f k .

3. The audio adjustment method of claim 1 , wherein the single tone is received by an audio receiver, wherein the audio receiver is installed in an artificial head device, the artificial head device comprises a human ear mechanism, and the audio receiver is installed in the human ear mechanism.

4. The audio adjustment method of claim 1 , wherein the energy corresponding to said each frequency f k is P k =E(|c k *r m | 2 ), wherein E is a function symbol, r m is an audio signal received based on the m th set of coefficients, and c k is a band-pass filtering coefficient.

5. The audio adjustment method of claim 1 , wherein an operating environment of the audio adjustment method is an anechoic environment.

6. An audio adjustment device, comprising:

an external audio source, configured to broadcast a single tone;

an earphone;

an artificial head device, comprising an audio receiver, configured to receive the single tone, wherein the earphone is positioned on the artificial head device; and

an audio adjustment circuit, coupled to the artificial head device, configured to perform the following operations:

obtaining multiple optimal noise cancellation responses of multiple frequencies, comprising:

for each frequency f k of the multiple frequencies:

controlling the external audio source to broadcast the single tone having said each frequency f k ;

generating M sets of filtering coefficients regarding said each frequency f k , wherein each set of filtering coefficients within the M sets of filtering coefficients comprises a combination of an amplitude and a phase, and the M sets of filtering coefficients are different from one another;

determining a m th set of filtering coefficients from the M sets of filtering coefficients to minimize energy corresponding to said each frequency f k , wherein the amplitude and the phase of the m th set of filtering coefficients represents an optimal noise cancellation response corresponding to said each frequency f k ; and

adjusting the single tone with the m th set of filtering coefficients to obtain an adjusted single tone corresponding to said each frequency f k for being broadcast by the earphone; and

determining a final set of active noise cancellation coefficients according to the multiple optimal noise cancellation responses of the multiple frequencies.

7. The audio adjustment device of claim 6 , wherein the artificial head device comprises a human ear mechanism, and the audio receiver is installed in the human ear mechanism.

8. The audio adjustment device of claim 6 , wherein the operations of the audio adjustment circuit further comprise:

utilizing an amplitude and a phase corresponding to the m th set of filtering coefficients to be a frequency response of said each frequency f k ; and

determining the adjusted single tone according to the frequency response of said each frequency f k .

9. The audio adjustment device of claim 6 , wherein the energy corresponding to said each frequency f k is P m =E(|c k *r n | 2 ), wherein E is a function symbol, r m is an audio signal received based on the m th set of coefficients, and c k is a band-pass filtering coefficient.