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本文讨论了一种新的调幅立体声信号的产生方法(用正交调制)和解调方法(用考斯塔斯Costas解调器即同相正交环或锁相环)。其波形为(1+L+R)cos(cot+φ),此处:φ=0.5arcsin[(L+R)/(1+L+R)],L和R为立体声信号。将此信号的边带频谱与调幅-调相制(AM-PM)的边带相比,本制式的带外辐射降低了而信噪比降低不多。本文介绍了本制式的优点,并建议用在欧洲中波调幅广播中。
This article discusses a new generation of AM stereo signal (using quadrature modulation) and demodulation (using Costas demodulator called in-phase orthogonal loop or phase locked loop). The waveform is (1 + L + R) cos (cot + φ) where φ = 0.5 arcsin [(L + R) / (1 + L + R)] and L and R are stereo signals. By comparing the sideband spectrum of this signal with the sideband of AM-PM, the out-of-band emissions of this system are reduced and the signal-to-noise ratio is not much reduced. This article describes the advantages of this standard and is recommended for use in European AM AM broadcasting.