Abstract: 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.

Abstract: An OFDM synchronization demodulation circuit includes a receiving circuit for receiving an orthogonal frequency division multiplexing (OFDM) modulation signal. An orthogonal detection circuit orthogonally detects the OFDM modulation signal from the receiving circuit using a detected carrier. A demodulation circuit orthogonally demodulates the detected OFDM multiplex modulation signal from the orthogonal detection circuit by sampling the OFDM multiplex detection signal using a detected clock. A constellation analyzing circuit analyzes the constellation of demodulated symbols of predetermined carriers in the demodulated OFDM multiplex signal signal. A carrier frequency deviation detection circuit detects a frequency deviation of the detected carrier based on a rotation of the constellation of the demodulated symbol detected by the constellation analyzing circuit.

Abstract: An OFDM synchronization demodulation circuit includes a recovery circuit, an orthogonal axis demodulation circuit, a first and second delay circuit, a correlation calculation circuit, a guard timing detection circuit, and an OFDM signal demodulation circuit. The receiving circuit receives an orthogonal modulated wave based on an orthogonal frequency division multiplex (OFDM) modulated signal having an available symbol period and a guard period, where the guard period of the orthogonal modulated wave is based on a part of the available symbol period. The orthogonal axes demodulation circuit demodulates an in-phase axis detection signal and an orthogonal axis detection signal for the OFDM modulated wave from the receiving circuit using orthogonal detection. The first delay circuit delays the in-phase axis detection signal by the available symbol period, and the second delay circuit delays the orthogonal axis detection signal by the available symbol period.