Communication device and echo cancellation method thereof

A communication device, adapted to implement full-duplex data transmission, and comprising:

• a transmitting circuit, receiving a digital output signal to generate an analog output signal;
• a receiving circuit, receiving an analog input signal to generate a digital input signal;
• a digital echo canceller, coupled to the transmitting circuit and the receiving circuit, and generating an echo energy indicator according to the digital output signal and the digital input signal;
• a transceiving front-end circuit, coupled to the transmitting circuit, and receiving the analog output signal and generating a hybrid interface signal;
• a hybrid fine-tune circuit, coupled to the digital echo canceller, and generating a first capacitance calibration signal and a second capacitance calibration signal according to the echo energy indicator;
• and
• an analog echo cancellation circuit, receiving the first capacitance calibration signal and the second capacitance calibration signal, and comprising a first variable capacitor and a second variable capacitor controlled by the first capacitance calibration signal and a third variable capacitor and a fourth variable capacitor controlled by the second capacitance calibration signal, wherein the analog echo cancellation circuit receives the analog output signal and the hybrid interface signal, and generates the analog input signal according to the first capacitance calibration signal and the second capacitance calibration signal.