| 摘要 |
PURPOSE:To attain optimum gain control by making the number of signal point positions included in a maximum amplitude level error area coincide with the number of signal point positions included in a minimum amplitude level error area. CONSTITUTION:A demodulating device is constituted of a QAM demodulator 1 and P-channel system 8a and a Q-channel system 8b which are connected to the post stage of the QAM demodulator 1. The channel systems 8a, 8b are respectively provided with automatic gain control circuits 2a, 2b, A/D converters 3a, 3b, signal converting circuits 4a, 4b, error signal selecting circuit 5a, 5b, control point number converting circuits 6a, 6b, and control signal forming circuits 7a, 7b. The circuits 6a, 6b make the number of signal point positions included in the minimum amplitude level error area coincide with that included in the maximum amplitude level error area and balanced gain control signals are formed by the circuits 7a, 7b. |
