PAL信号的亚奈奎斯特压缩编码的混叠消除

Dispersion Confusion of PAL Signal Sub Liguist Compress Encode

高清晰度数字电视 (HDTV)对 PAL彩色全电视信号采用 4 fsc抽样 ,其数码率 4 2 5.6 2 74Mbit/s。在编码端对其采用 2 fsc亚奈奎斯特压缩编码 ,可将传送码率压缩一半 ;在接收端 ,由解码器将 2 fsc亚奈奎斯特压缩码插值还原为 4 fsc码。文中分析了由 4 fsc转化为 2 fsc PAL彩色全电视数字信号的亚奈奎斯特压缩编码的频谱结构 ,建立了在发送端编码器和接收端解码器的电路模型 ;研究了对应混叠区的特定形状梳状滤波器对突变图像亮度信号在半行频点频谱的抑制作用和对混叠分量的滤除作用 ;根据 PAL色度信号 CU,CV 分量的副载频 4行 1循环特点 ,得到在编码器和解码器内的梳状滤波器共同作用能克服混叠分量对色度信号的失真影响的结论。实验结果表明 ,文中方法达到了消除亮度和色度混叠的效果。

In the high definition digital television (HDTV), PAL TV signal is sampled with 4 f sc . The code rate is 425.627 4 Mbit/s. In the encoder it is compressed into 2 f sc with Sub Liguist encoder. At the receiving end, the 2 f sc Sub Liguist encoder is restored to 4 f sc in a decoder by inserting signals. This paper analyzes the structure of PAL color TV signal that have been encoded and compressed in PAL color signal sample from 4 f sc to 2 f sc . A circuit model of encoder in input and decoder in output is set up. The distinctive comb filters are studied that dispose changing Y frequency in ( n±0.5) f H and its confusion. According to f sc of PAL color signal that has a cycle of 4 T H , comb filters are proved to be capable of correcting color phases by experiments.