| 摘要 |
PURPOSE:To prevent a reception image from deteriorating by controlling an A/D converter, the equalizer of a demodulation circuit, and a phase circuit by the output of a control signal decision circuit which decides the output signal of a signal processing circuit. CONSTITUTION:In a demodulation side modem including a transmission system, the demodulation circuit is comprised of a QAM(quadrature amplitude modulation) demodulator 2, the equalizer 4, the phase circuit (rotating apparatuses 11, 13, decision apparatus 12, phase estimation part 10), and a timing estimation part 5. Timing estimation is performed by estimating a sampling rate, and phase estimation by estimating a carrier, and the equalizer 4 corrects frequency characteristic received by a transmission signal on a transmission line. An output facsimile signal can be obtained by controlling the A/D converter 1, the equalizer 4 of the demodulation circuit, and the phase circuit by the output of a control signal decision circuit 16 which decides the output signals of those signal processing circuits. |
