Ben Bradley wrote: ...> That's an "interesting" discussion but doesn't give a clue about > the internals of "digitally controlled Class D." > > Googling found this paper which has some technical meat - it > mentions regular PWM, digital-input PWM, and "Direct delta-sigma > modulation" that is exactly what I was thinking of::> http://www.chipidea.com/essderc2003/presentations/esscirc/c30/005_47_updated.pdf... Thanks for hunting it down. I can see this sub-thread degenerating into an interminable (at any rate, unterminating) argument over the meaning of words. I'll get my licks in early, then run for cover and duck. As far as I'm concerned, converting two's complement binary to PWM is an D-to-A operation, despite the binary nature of the pulses' amplitudes. Properly, "analog" as we use it is a misnomer, as is "digital" when applied to gates and flip-flops. Digital is about numbers, analog is the representation of one quantity as analogous to another, as voltage being an analog of, say, mass. Despite that, we know what we mean by analog and digital and if we don't "mere sandwich"* our terms, we won't get sidetracked. I claim that a box that accepts numbers and provides drive to a voice-coil speaker necessarily does D-to-A conversion. The circuit referred to does it before the H bridge. Jerry _______________________________________________ * When one is famished, nothing is better than a solid meal. A mere sandwich, however, is better than nothing. A>B>C implies A>C. When one is famished, nothing is better than a mere sandwich. -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Re: Power conversion. (was "Opposite of Mu-law?")
Started by ●May 24, 2004
