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YONG牌CDG-666机的DSP使用CXD2508Q芯片,其内置1Bit音频DAC,位时钟采用33.8688MHz。此种机改装VCD机,若解压板无自带的16.93MHz晶振,则需对CD机33.86MHz位时钟频带进行二分频处理,而后送入解压板的16.93MHz线端,否则VCD的放音速度将会加快一倍。笔者改装时,二分频电路,采用高速CMOS双D触发器74HC74中的一个D触发器,以最简的方法取得16.93MHz。具体电路如图所示。
YONG card CDG-666 machine uses CXD2508Q DSP chip, its built-in 1Bit audio DAC, bit clock with 33.8688MHz. Such machines modified VCD machine, if the decompression board without their own 16.93MHz crystal, you need to CD-ROM 33.86MHz bit clock frequency band for two-way processing, and then into the decompression board 16.93MHz line, or VCD playback Speed will be doubled. When I modified, the second frequency circuit, the use of high-speed CMOS dual-D flip-flop 74HC74 a D flip-flop, in the most simple way to obtain 16.93MHz. Specific circuit as shown.