[time-nuts] GPSDO control loops and correcting quantization error
Poul-Henning Kamp
phk at phk.freebsd.dk
Sun Sep 16 06:21:05 UTC 2012
In message <1225454799-1347767280-cardhu_decombobulator_blackberry.rim.net-1901
834519- at b27.c1.bise6.blackberry>, lists at lazygranch.com writes:
>The PWM DAC should have perfect differential linearity, which I
>believe is all that matters in this application. (That and no missing
>codes.) Not so when you try to combine two DACs to make one higher
>resolution DAC.
The main problem with two staggered DAC's is actually that all OCXO's
drift and eventually you will have to step the major DAC which will give
a glitch in the lower bits, almost no matter how much you calibrate
beforehand.
The PRS10 uses a staggered DAC internally and the steps on the major
DAC are measurable in the output signal.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
More information about the time-nuts
mailing list