Method for dynamically adjusting gain of parametric equalizer according to input signal, dynamic parametric equalizer and dynamic parametric equalizer system employing the same

1. A parametric equalizer having a transfer function H(z) with a preset gain G as a parameter, the parametric equalizer dynamically adjusting the preset gain G, the parametric equalizer comprising:

a first signal processing unit having a transfer function H 1 , the first signal processing unit being configured to process an input digital audio signal X according to the transfer function H 1 and output a first output signal obtained by processing the input digital audio signal X;

a second signal processing unit having a transfer function H 2 of a level Gin of the first output signal, the second signal processing unit being configured to process the first output signal according to the transfer function H 2 and output a second output signal obtained by processing the first output signal; and

an adder configured to add the second output signal to the input digital audio signal X to generate an output digital audio signal Y (where H 1 =[H(z)−1]/(G−1), H 2 =G−1 when 0<Gin<1/G, H 2 =1/Gin−1 when 1/G≦Gin≦1 and H 2 =0 when 1<Gin).

2. The parametric equalizer according to claim 1 , wherein Y=H(z)X when 0<Gin<1/G.

3. The parametric equalizer according to claim 1 , wherein a level of the output digital audio signal Y is maintained by monotonically decreasing the preset gain G when 1/G≦Gin≦1.

4. The parametric equalizer according to claim 1 , wherein the output digital audio signal Y is equal to the input digital audio signal X when 1<Gin.

5. A method of dynamically adjusting a preset gain G of a parametric equalizer having a transfer function H(z) with the preset gain G as a parameter, the method comprising:

(a) inputting an input digital audio signal X to a first signal processing unit having a transfer function H 1 and processing the input digital audio signal X according to the transfer function H 1 to generate an output signal Y 1 ;

(b) inputting the output signal Y 1 to a second signal processing unit having a transfer function H 2 of a level Gin of the output signal Y 1 and processing the output signal Y 1 according to the transfer function H 2 to generate an output signal Y 2 ; and

(c) adding the output signal Y 2 to the input digital audio signal X to generate an output digital audio signal Y (where H 1 =[H(z)−1]/(G−1), H 2 =G−1 when 0<Gin<1/G, H 2 =1/Gin−1 when 1/G≦Gin≦1 and H 2 =0 when 1<Gin).

6. The method according to claim 5 , wherein Y=H(z)X when 0<Gin<1/G.

7. The method according to claim 5 , wherein a level of the output digital audio signal Y is maintained by monotonically decreasing the preset gain G when 1/G≦Gin≦1.

8. The method according to claim 5 , wherein the output digital audio signal Y is equal to the input digital audio signal X when 1<Gin.

9. A parametric equalizer system having a transfer function H(z) with a preset gain G as a parameter, the parametric equalizer dynamically adjusting the preset gain G, the parametric equalizer comprising:

a first signal processing unit configured to process a signal X 1 according to the transfer function H 1 to generate an output signal Y 1 ;

a level detector configured to detect a level Gin of the output signal Y 1 ;

a second signal processing unit configured to process the output signal Y 1 according to the transfer function H 2 of the level Gin detected by the level detector to generate an output signal Y 2 ; and

an adder configured to add the output signal Y 2 to the signal X 1 to generate an output digital audio signal Y (where H 1 =[H(z)−1]/(G−1), H 2 =G−1 when 0<Gin<1/G, H 2 =1/Gin−1 when 1/G≦Gin≦1 and H 2 =0 when 1<Gin).

10. The parametric equalizer system according to claim 9 , wherein Y=H(z)X 1 when 0<Gin<1/G.

11. The parametric equalizer system according to claim 9 , wherein a level of the output digital audio signal Y is maintained by monotonically decreasing the preset gain G when 1/G≦Gin≦1.

12. The parametric equalizer system according to claim 9 , wherein the output digital audio signal Y is equal to the signal X 1 when 1<Gin.

13. The parametric equalizer system according to claim 9 , further comprising a volume controller configured to generate the signal X 1 by adjusting a level of an input digital audio signal X.

14. A method of dynamically adjusting a preset gain G of a parametric equalizer having a transfer function H(z) with the preset gain G as a parameter, the method comprising:

(a) inputting a signal X 1 to a first signal processing unit having a transfer function H 1 and processing the signal X 1 according to the transfer function H 1 to generate an output signal Y 1 ;

(b) detecting a level Gin of the output signal Y 1 ;

(c) inputting the output signal Y 1 to a second signal processing unit having a transfer function H 2 of the level Gin detected in the step (b) and processing the output signal Y 1 according to the transfer function H 2 to generate an output signal Y 2 ; and

(d) adding the output signal Y 2 to the signal X 1 to generate an output digital audio signal Y (where H 1 =[H(z)−1]/(G−1), H 2 =G−1 when 0<Gin<1/G, H 2 =1/Gin−1 when 1/G≦Gin≦1 and H 2 =0 when 1<Gin).

15. The method according to claim 14 , wherein Y=H(z)X 1 when 0<Gin<1/G.

16. The method according to claim 14 , wherein a level of the output digital audio signal Y is maintained by monotonically decreasing the preset gain G when 1/G≦Gin≦1.

17. The method according to claim 14 , wherein the output digital audio signal Y is equal to the signal X 1 when 1<Gin.

18. The method according to claim 14 , further comprising generating the signal X 1 by adjusting a level of an input digital audio signal X prior to performing the step (a).