Quadrature demodulator and method for quadrature demodulation

摘要

A quadrature demodulator detects a phase angle error determined from the phase angle supplied from constellation symbols of outgoing in-phase and quadrature components of a modulated signal and and the phase angle of a NCO. The quadrature demodulator comprises a receiving circuit for receiving a quadrature modulated signal, and a local oscillator for generating a local carrier. A complex multiplier demodulates the quadrature modulated signal by complex-multiplying the quadrature modulated signal with the local carrier generated in the local oscillator. A symbol error detector detects a symbol error between the carrier of the modulated signal and the local carrier supplied from the signal demodulated at the complex-multiplier. A feedback loop controls the local carrier generated at the local oscillator by feeding back the symbol error detected at the symbol error detector to the local oscillator.