| 摘要 |
PURPOSE:To limit a pull-in phase in a demodulating equipment to one and to unify a bit error rate characteristic by dislocating the phase difference between two systems of a currier from a pi/2 radian to a suitable angle DELTAtheta radian in respective modulating equipment and demodulating equipment. CONSTITUTION:The phase transition quantity of phase transition devices 8 and 13 provided at a modulating equipment and a demodulating equipment is respectively a (pi/2-DELTAtheta) radian or a (pi/2+DELTAtheta). Consequently, the modulating equipment orthogonal-amplitude-modulates a carrier having the phase difference in the (pi/2-DELTAtheta) radian or the (pi/2+DELTAtheta) radian mutually with the multi-value base band signal of two columns and obtains a modulated signal. The demodulating equipment synchronizes and detects the received and inputted modulated signal with a reproducing carrier having the phase difference in the (pi/2-DELTAtheta) radian or the (pi/2+DELTAtheta) radian mutually, multi-value-identifies it and obtains the base band signal. At the demodulating equipment when the pull-in phase is different from a modulating equipment side, a control loop shifts the control in the direction to reduce the bit error rate. Thus, the pull-in is executed by one specified phase and a demodulating action having a constant bit error rate characteristic is executed.
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