I did not see any such setting in the Rigol, but I'll check again. in April I did write to Rigol to report the problem and had the following (abridged) conversation with support:
Me: "I recently tried to use your DG1022Z signal generator to generate one pulse-per-second (pulse mode, frequency 1.000000hz, width 10 microseconds). However, it appears there is a small frequency error of one part in 1e11, i.e. the pulse per second gets later by about 6 nanoseconds every 1,000 seconds." [More technical description abridged, including a link to a graph.] Rigol: "Please find the following datasheet for DG1000Z, the accuracy is +/-1ppm. If your pulse is 1second with 10us width, 6ns per 1000s is in the accuracy range." [They attached an image of a page from the DG1000Z datasheet, showing a line that said "Accuracy: +/- 1ppm of the setting value"] Me: "Is this the specification even when the unit is provided with an accurate external clock?" Rigol: "I would say Yes. The internal processing circuit will effect the clock signal, harmonics and phase noise will result the frequency variance." -Jeremy On Sun, Nov 21, 2021 at 11:54 PM Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > -------- > Jeremy Elson writes: > > > [...] I plugged an RbXO into the DG1022Z and simply asked the > > DG1022Z to divide it down to a 1pps signal. That is, I configured it to > > create a pulse with a small duty cycle and 1hz frequency using the > external > > clock as a reference. To my surprise, it introduces a small but > > measurable error of one part in 1E11 in the dividing-down. You can read > the > > full story of this in my post from earlier this year: > > When you feed such instruments an external clock, you often have to change > one or more calibration constants for the internal (OC)XO's offset to zero. > > Another problem is that if you use the square wave output of a DDS based > generator, they often produce the square from the sine output of > the DDS chip with a schmitt-trigger, which causes lousy jitter. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@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. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
