Multi-channel decoding systems capable of reducing noise and methods thereof

1. A multi-channel decoding system, comprising:

a decoding circuit, for receiving an input signal to generate a channel output signal;

a test signal generating circuit, for providing a first test signal serving as the input signal in a first calibration mode; and

a calibration circuit, for adjusting a DC voltage level of the channel output signal outputted by the decoding circuit with a first calibration signal by reducing a difference between a first predetermined reference signal level and a DC voltage level of the channel output signal generated from the first test signal.

2. The multi-channel decoding system of claim 1 , wherein the calibration circuit comprises:

a comparison module, for comparing the DC voltage level of the channel output signal generated from the first test signal with the first predetermined reference signal level to output a first comparison result of the first calibration mode; and

a decision module, for adjusting the first calibration signal according to the first comparison result.

3. The multi-channel decoding system of claim 2 , wherein the decision module comprises:

a decision unit, for determining a first digital code according to the first comparison result; and

a digital-to-analog converter, for converting the first digital code into a first voltage serving as the first calibration signal.

4. The multi-channel decoding system of claim 3 , wherein the decision unit utilizes a digital successive-approximation algorithm to determine the first digital code.

5. The multi-channel decoding system of claim 1 , wherein the test signal generating circuit is arranged to provide a second test signal serving as the input signal in a second calibration mode; the calibration circuit is arranged to adjust the DC voltage level of the channel output signal outputted by the decoding circuit with a second calibration signal by reducing a difference between a second predetermined reference signal level and a DC voltage level of the channel output signal generated from the second test signal; and one of the first calibration mode and the second calibration mode is a mono calibration mode and the other of the first calibration mode and the second calibration mode is a stereo calibration mode.

6. The multi-channel decoding system of claim 5 , wherein the first test signal is identical to the second test signal.

7. The multi-channel decoding system of claim 1 , wherein the first test signal is a square wave signal; and the decoding circuit comprises:

a demodulator, for demodulating the square wave signal into a DC signal; and

a signal processing module, for generating the channel output signal according to the DC signal.

8. A multi-channel decoding method, comprising:

receiving an input signal to generate a channel output signal;

providing a first test signal serving as the input signal in a first calibration mode; and

adjusting a DC voltage level of the channel output signal with a first calibration signal by reducing a difference between a first predetermined reference signal level and a DC voltage level of the channel output signal generated from the first test signal.

9. The multi-channel decoding method of claim 8 , wherein the step of adjusting the DC voltage level of the channel output signal comprises:

comparing the DC voltage level of the channel output signal generated from the first test signal with the first predetermined reference signal level to output a first comparison result of the first calibration mode; and

adjusting the first calibration signal according to the first comparison result.

10. The multi-channel decoding method of claim 9 , wherein the step of adjusting the first calibration signal according to the first comparison result comprises:

determining a first digital code according to the first comparison result; and

converting the first digital code into a first voltage serving as the first calibration signal.

11. The multi-channel decoding method of claim 10 , wherein the step of determining the first digital code according to the first comparison result comprises:

utilizing a digital successive-approximation algorithm to determine the first digital code.

12. The multi-channel decoding method of claim 8 , further comprising:

generating a second test signal serving as the input signal in a second calibration mode; and

adjusting the DC voltage level of the channel output signal with a second calibration signal by reducing a difference between a second predetermined reference signal level and a DC voltage level of the channel output signal generated from the second test signal;

wherein one of the first calibration mode and the second calibration mode is a mono calibration mode and the other of the first calibration mode and the second calibration mode is a stereo calibration mode.

13. The multi-channel decoding method of claim 12 , wherein the first test signal is identical to the second test signal.

14. The multi-channel decoding method of claim 8 , wherein the first test signal is a square wave signal; and the step of receiving the input signal to generate the channel output signal comprises:

demodulating the square wave signal into a DC signal; and

generating the channel output signal according to the DC signal.