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CD机升级为VCD机,目前一般均采取从原CD机DSP芯片后级取用BCK(基准时钟)、DATA(数据)、LRCK(左右时钟)信号,然后通过一块MPEG解压板对数据进行解压缩、编码、处理,最后送出音频视频信号。实践证明,该方案存在下列缺陷:(1)局限性大,不是所有CD机和LD机都能按此方案改装,如CD机、LD机带软静噪时就无法改装;(2)一致性差,改装效果与原机机心及DSP芯片纠错能力关系很大,改装后播放VCD盘片时,停顿、马赛克现象严重;(3)由于改装时要修改DSP芯片的模式,去掉数字滤波器,导致改装后原机电性能降低,得不偿失。
CD player upgrade to VCD machine, at present generally take from the original CD machine DSP chip access BCK (reference clock), DATA (data), LRCK (left and right clock) signal, and then through an MPEG decompression board to decompress the data , Coding, processing, and finally send audio and video signals. Practice has proved that the program has the following shortcomings: (1) the limitations of large, not all CD player and LD machine can be modified according to this program, such as CD machine, LD machine with soft mute can not be modified; (2) poor consistency , The modification effect and the original machine movement and DSP chip error correction ability is very big, after the modification broadcast VCD disc, the pause, the mosaic phenomenon is serious; (3) because the modification must revise the DSP chip pattern, removes the digital filter, Lead to the original mechanical and electrical properties after modification to reduce, outweigh the benefits.