Demodulator and phase compensation method thereof

A phase compensation method of a demodulator, the method comprising:

• detecting a phase shift of a received digital signal after a semi-synchronous detection to a predefined phase position;
• compensating for a phase of the received digital signal by a first compensation value on the basis of the detected phase shift to generate an output signal;
• averaging an value of the detected phase shift;
• and
• compensating for a phase of a signal compensated with the first compensation value by a second compensation value on the basis of an averaged value.

A demodulator comprising:

• a quadrature detector which converts a received signal to base-band signals of in-phase channel and quadrature-phase channel with multiplying by a local oscillation frequency;
• low-pass filters which eliminate high frequency components more unnecessary from the base-band signals;
• analog-to-digital converters (A/D) which convert the base-band signals after filtering into digital signals;
• a carrier recovery loop which detects a phase shift of the digital signals to a predefined phase position, and compensates for a phase of the digital signal by a first compensation value on the basis of the detected phase shift to generate an output signal;
• and
• a feed-forward phase compensation loop which generates an average value of the detected phase shift, and compensates for a phase of a signal output from the carrier recovery loop by a second compensation value on the basis of the averaged phase shift.