thank ryan a lot .
Those information is very useful.
Added after 7 minutes:
i encounter another problem , and really wanna to ask you
About my DPWM system , it will receive the PCM signal ( with 16 bits and 44.1khz) and transfer to 12 bits and 200 khz sampling. I want to know
1) since i receive the PCM signal , and it related to the Compact Disk (CD 44.1khz and 16 bits ) , i want to know how the player detect the information from CD
2) PCM signal : before the PCM sigal producing , we need to sampling and quantize the signal right ? but for PCM case , the quantize is unsigned value ( 0 -> 2^16 -1) or signed value
Regards