| ??? 05/16/08 16:13 Modified: 05/16/08 16:17 Read: times |
#154826 - Not very, apparently. Responding to: ???'s previous message |
Richard Erlacher said:
If your adc is an 8-bitter, you need your analog power supply and, particularly, your reference, to be no noisier than 1%. That means that, under full load and maximal external perturbation, the variation on the supply is still less than 5 mV.
I'm guessing a 39mV sawtooth straight out of my PSU isn't helping much. >>edit: Isn't that 1.2% though? 
Richard Erlacher said:
A small cap on the wiper of your POT might be a big help, too, BTW. In series with the wiper, or to ground (sorry if that's a dumb question). Thanks for your comprehensive reply Richard. I think this is a good place for me to start from the look of things. Interestingly, the output from the pot wiper shows this intereference varying with position. Sometimes the output voltage is dead flat, other times it has this ripple on it. A function of RC? I have a bypass cap straight across both ends of the pot. |
