On 03/01/2017 01:40 AM, Jim Brain via cctalk wrote: > On 2/28/2017 2:34 PM, Brent Hilpert wrote: snippage > Obviously, given the LM339 issues, this is unworkable in the end, but > it did get me to realizing some outputs on the LM339, so thanks to > both of you. > > I can plainly see the oscillation on the comparator transitions, so it > is obvious I need a better comparator. I'll have to source a few > different comparator options from Digikey to fill my parts box. > Suggestions are welcome. OR a bit of positive feedback.
>> Using the internal AVR comparator sounds like a better final solution >> (fewer components), but in devising an >> input circuit for the AVR you may be running into the same issue of >> loading a high-impedance source. > Though it plays into Tonly's notes about my analog understanding (or > lack thereof), I was so disillusioned by the analog uncertainties that > I initial focused on the AVR comparator. By correctly biasing the > comparator, I was able to get much better results tonight, but the > lack of any ability to add hysteresis into the design hindered my > success. At transition, the signal simply bounces badly. I tried to > construct a low pass filter (22pF and 5K6), and some variations, but I > was not able to overcome. I then tried to deal with it in SW, but I > have not yet been successful. I'll try again, but lack of hysteresis > is a big issue. > Single transistor audio amp before it. Allison > Jim > >
