Quadrature demodulator for compensating for gain and phase imbalances between in-phase and quadrature-phase components

A quadrature demodulator for high-speed wireless communication, comprising:

• an A/D converter for converting a received signal into a digital signal;
• a signal recovery unit for recovering carriers and symbol timing from the signal converted by the A/D converter and outputting a recovered signal;
• a decision unit for detecting the recovered signal output by the signal recovery unit, and performing a decision process on the recovered signal;
• an I/Q phase imbalance detector for applying a signal value difference between the recovered signal and a signal output by the decision unit to the respective I and Q-phase components by performing an AGC (automatic gain control) operation according to a code of the recovered signal to detect phase imbalances between the I and Q-phase components, and outputting an I/Q phase compensation value for compensating for the phase imbalances;
• and
• an I/Q phase compensator, provided between the A/D converter and the signal recovery unit, for reflecting the I/Q phase compensation value output by the I/Q phase imbalance detector to the received signal.

A quadrature demodulator for high-speed wireless communication, comprising:

• an A/D converter for converting a received signal into a digital signal;
• a signal recovery unit for recovering carriers and symbol timing from the signal converted by the AID converter and outputting a recovered signal;
• a decision unit for detecting and determining the recovered signal output by the signal recovery unit;
• an I/Q gain imbalance detector for detecting gain imbalances of the I and Q-phase components from the recovered signal, wherein the I/Q gain imbalance detector computes a ratio of the I and Q-phase components to generate an output of an I/Q gain compensation value for compensating for the gain imbalance;
• an I/Q phase imbalance detector for applying a signal value difference between the recovered signal and a signal output by the decision unit to the respective I and Q-phase components according to a code of the recovered signal to detect phase imbalances between the I and Q-phase components, and outputting an I/Q phase compensation value for compensating for the phase imbalances;
• an I/Q gain compensator, provided between the A/D converter and the signal recovery unit, for reflecting the I/Q gain compensation value output by the I/Q gain imbalance detector to the received signal;
• and
• an I/Q phase compensator, provided between the I/Q gain compensator and the signal recovery unit, for reflecting the I/Q phase compensation value output by the I/Q phase imbalance detector to the received signal.