I am working on an amplifier design, and I was thinking about using a
class D,G,or H design.  Could someone please give me a hint on how to
implement the pulse width modulation that is necessary for these
topologies?  I was thinking that I could just use a sample and hold
device off the output and compare that value with the current input at set
intervals.  Is this how PWM works, or is it more complicated?

Just so I'm not chastised for asking this question...there is a PIC
involved.

Thanks,

Stuart Allman
studio@halcyon.com