Conventional dual up-conversion transmitter usually employs an intermediate frequency (IF) mixer and a radio frequency (RF) mixer to convert baseband user signal to IF and RF in sequence.
Firstly the basic transmitter, including convolutional encoding, interleaving, scrambling, Walsh modulation, quadrature spreading and baseband filtering was studied.
首先研究基本的发射机，包括卷积编码、交织、扰码、沃尔什调制、正交扩频以及基带滤波。
3
SHD-A model transmitter is applied to emit and convey baseband signal of sound, vibration and measure-control in aeronautical communication system from one point to multi-point.