digital Class D amplifier

[clarken]

Now i am doing the digital Class D amplifer( digital PWM). When reading the sampling , i encounter some doubts: natural sampling and uniform sampling. They said that the natural requires a very high clock frequency( ex 48khz sampling rate with 12 bit resolution requires 48khz x 2^12) for high resolution.. I dun know why and also dun know what is the clock they mention here. Anyone knew how to answer ??

Thax

 

[RDRyan]

As I know, if data is 12 bit resolution, PCM code has 2^12 different value, so that means the pulse width of PWM must has 2^12 different width. and we need a clock frequency of 2^12 times PCM clock to convert PCM to PWM in a one PCM clock.
So, the high clock frequency is 48kHz*2^12.

Ryan

 

[clarken]

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