Yes, the DAC+reference is challenging and one way to go may be the coarse+fine approach to avoid large (18bit and beyond) DAC. My last GPSDO has an 18bit DAC but now I'm thinking to try the 8bit digital pot + 16bit DAC op-amp combined. The reference can't be overlooked anyway.
On Fri, Dec 30, 2011 at 10:24 PM, Stanley <[email protected]> wrote: > The DAC and it's voltage reference looks to be the weak link in the > digital control and the "simple" goal. The CPU I mentioned before on closer > look doesn't have a good DAC. The 20 bit TI DAC1220 looks better but not > sure you can find it in the same package as the CPU. The cheap Rb standards > with digital control would not need a DAC and maybe this points to a > simpler GPSDO that doesn't control the XO with analog but corrects it with > a DDS but again finding them both in one chip is the problem. I have seen > OCXO and DAC in the same package and even the DDS and OCXO combined but > they didn't fit the simple goal. Not even sure how good they were. I know > they are hard to find. > > Stanley > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
