-------- In message <5741e08b.9080...@rubidium.dyndns.org>, Magnus Danielson writes:
>The negative voltage switcher of A15 board should be replaced with a >suitable switcher, and some of the DC/DC switcher modules is built with >isolation, so it should allow for mounting two in parallel such that you >get both sides. PHK, have you checked this option? Yes and no. I think the +/- 20V *should* not matter, and the reason they currently do is something a couple of well-chosen modern op-amps can take care of as far as I can tell. My hope was to design a couple of plug-in replacement boards to fix most of these issues, while allowing A/B comparisons to the improvement can actually be measured. Basically: A new integrator board, using a modern chopper/zero-drift op-amp. A new AC amplifier, ditto. Instead of the two diodes, put a modern "ideal diode" circuit and two DC/DC converters on the first PSU board, producing the +24V and a -15V rail for the rest of the instrument. (-15 instead of -20 since it will be driving the opamps mentioned above. On the second board, an opamp to drive the existing chassis-mounted +20V series transistor from a _really_ good voltage reference (LM399) and the most stable C-field drive circuit I can come up with. But as I said, I'm just about to start building a new house, so my time is limited for the next year or so... If somebody else wants to take the lead, I'll happily assist as I can... The "NextGen" project, would be to use a 48bit DDS chip to generate the 60+MHz drive signal for the microwave, and a "geophone" ADC chip to detect the modulation from the photo-diode, but that is even further out... -- 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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.