> Another approach is to distribute the individual bits rather than clump them > together. If you want 1/2, send 10101010 rather than 11110000. You would > have to do something like build a bit pattern in memory and use a serial > port to send it out.
> I can't determine if that's good enough. I think the math is similar to the > spurs you get from a DDS. I'm getting slow in my old age... You can also generate the bit pattern on the fly. It's the same logic as a DDS: just an adder. If you want the D/A to output X (as a fraction) just add X to your register each clock cycle. (I think of the register as having the decimal point on the left.) With a DDS, you would feed the top bits to a D/A. For the distributed PWM (Pulse Density Modulation?) use the carry out of the top bit. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.