正交独立边带制调幅立体声广播的探讨

Exploring of AM Stereo Broadcasting of QUAM-ISB

本文提出的正交调幅独立边带制(QUAM-ISB),综合了目前世界上存在的调幅立体声制式的优点。它利用了正交调制技术,主副频道的音频信号分别调制在一对互相正交的载频上,发射信号的调幅分量与MOTOROLA制一样进行修正,因而获得了综合性能较好的优点;另一特点是主副信道的音频信号在调制之前已移相90°,因此发射信号的频谱具有独立边带特性。它与正交特性相比具有与KAHN制相同的特性。本文详细地讨论了正交独立边带制的构成及发射机与接收机的方框图,然后利用CAA技术分析与计算了发射信号的频谱,最后研究了它的一些基本特性。

The QUAM-ISB format Presented here has the advantages of the existing AM stereo formats.The first advantage is its comprehensive performance is vcry good.With quadrature modulation technique,its audio signals in main channel and subchannel are respectively modulated on two quadrature carrier-frequencies and the AM component of transmitting signal, as in MOTOROLA format,is modified.The second one is the spectrum of transmitting signal has the characteristic of independent sideband,because audio signals in main channel and subchannel have been phase-angled 90° before modulation.comparing with quadrature characteristic it has the same feature as KAHN format does. Here the QUAM-ISB's comoosition is discussed in detail and also block diagrams of transmitter and receiver are presented.Then transmitting signal's spectra are analysed and calculated with CAA technique.Last its some basic features are researched.