Signal processing apparatus and associated method

1. A signal processing apparatus, comprising:

a signal conversion circuit, for performing a signal conversion operation on a reception signal according to a first clock signal to generate a first output signal;

an amplitude adjustment circuit, coupled to the signal conversion circuit, for calculating an amplitude value of the reception signal according to the first output signal, and accordingly adjusting an amplitude of the reception signal and thereafter, the signal conversion circuit performs the signal conversion operation on the amplitude-adjusted reception signal according to a second clock signal to generate a second output signal; and

a phase adjustment circuit, for adjusting a phase of the second clock signal according to the second output signal;

wherein the reception signal is an amplitude shift keying (ASK) modulation final.

2. The signal processing apparatus according to claim 1 , wherein the reception signal comprises a carrier signal, and a frequency of the first clock signal is substantially a frequency four times of that of the carrier signal.

3. The signal processing apparatus according to claim 1 , wherein the reception signal comprises a carrier signal, and a frequency of the second clock signal is substantially equal to that of the carrier signal.

4. The signal processing apparatus according to claim 1 , wherein a specific phase of the second clock signal adjusted by the phase adjustment circuit is substantially aligned with a peak or a valley of the reception signal adjusted by the amplitude adjustment circuit.

5. The signal processing apparatus according to claim 1 , wherein the amplitude adjustment circuit comprises:

an amplitude calculation circuit, for calculating the amplitude value of the reception signal according to a result of a first sample point and a result of a second sample point from the first output signal; and

a gain adjustment circuit, for amplifying the reception signal according to the amplitude value of the reception signal and a signal operation range of the signal conversion circuit to adjust the amplitude of the reception signal.

6. The signal processing apparatus according to claim 5 , wherein a phase difference between the first sample point and the second sample point is substantially one quarter of a cycle of the reception signal.

7. The signal processing apparatus according to claim 6 , wherein the amplitude calculation circuit calculates the amplitude value of the reception signal by utilizing an equation: A 2 sin 2 (ω 0 t+φ) +A 2 sin 2 (ω 0 t+φ+90°), where A represents the amplitude value, A sin(ω 0 t+φ+90°) represents a voltage of the first sample point, A sin(ω 0 t+φ+90°) represents a voltage of the second sample point, ω 0 represents a frequency of a carrier signal of the reception signal, φ represents an angle, and t represents a time.

8. A signal processing method, comprising:

providing a signal conversion circuit, and

performing a signal conversion operation on a reception signal according to a first clock signal to generate a first output signal by the signal conversion circuit;

calculating an amplitude value of the reception signal according to the first output signal, and accordingly adjusting an amplitude of the reception signal;

performing the signal conversion operation on the amplitude-adjusted reception signal according to a second clock signal to generate a second output signal by the signal conversion circuit; and

adjusting a phase of the second clock signal according to the second output signal;

wherein the reception signal is an ASK modulation signal.

9. The signal processing method according to claim 8 , wherein the reception signal comprises a carrier signal, and a frequency of the first clock signal is substantially a frequency four times of that of the carrier signal.

10. The signal processing method according to claim 8 , wherein the reception signal comprises a carrier signal, and a frequency of the second clock signal is substantially equal to that of the carrier signal.

11. The signal processing method according to claim 8 , wherein in the step of adjusting the phase of the second clock signal according to the second output signal, a specific phase of the phase adjusted second clock signal is substantially aligned with a peak or a valley of the amplitude-adjusted reception signal.

12. The signal processing method according to claim 8 , wherein the step of calculating the amplitude value of the reception signal according to the first output signal and accordingly adjusting the amplitude of the reception signal comprises:

calculating the amplitude value of the reception signal according to a result of a first sample point and a result of a second sample point from the first output signal; and

amplifying the reception signal according to the amplitude value of the reception signal and a signal operation range of the signal conversion circuit to adjust the amplitude of the reception signal.

13. The signal processing method according to claim 12 , wherein a phase difference between the first sample point and the second sample point is substantially one quarter of a cycle of the reception signal.

14. A signal processing apparatus, comprising:

a signal conversion circuit, for performing a signal conversion operation on a reception signal according to a first clock signal to generate a first output signal;

an amplitude adjustment circuit, coupled to the signal conversion circuit, for calculating an amplitude value of the reception signal according to the first output signal, and accordingly adjusting an amplitude of the reception signal and thereafter, the signal conversion circuit performs the signal conversion operation on the amplitude-adjusted reception signal according to a second clock signal to generate a second output signal; and

a phase adjustment circuit, for adjusting a phase of the second clock signal according to the second output signal;

wherein a specific phase of the second clock signal adjusted by the phase adjustment circuit is substantially aligned with a peak or a valley of the reception signal adjusted by the amplitude adjustment circuit.