New project (start) on www.sm0vpo.com - CMOS timebase for oscilloscope

Just a little update. I am in Spain, same situation, but before I came here I built the prototype. Worked perfectly


Prototype waveform. Three micro-glitches at 25%, 50% and 75% at the fastest range (almost 100kHz)
Top range limited because of cable capacitance for the timing cap.


I used Arduina wires with the plugs ready fitted.
Green/blue is the timing cap.
Orange/yellow id the 12V power
8-bit D-A used 4K7 resistors.

Final version:
1 - 9-bit D-A for all but the fastest range, using 22K resistors
2 - Interface board will be a 7-bit D-A using 4K7
3 - Fewer links - board laid out a little differently
4 - I/F board will have a breakout for INH and RST for the trigger board

Just spent a few hours tidying it all up after corrections from prototype.
BR Harry - SM0VPO
(Still in Spain. Torrential rain. Corona lock-down. Hope to be home on Saturday on an emergency SAS flight. Only cost SEK11,000)

Hi all,
I am stuck in Spain, with no rig, no workshop - nada!
When they say "the rain in Spain falls mainly in the plain" don't you believe it. We have had three days of non-stop rain. Almost expecting the coming of another Noa. So I have spent a few hours (a lot of hours) on a new project, loosely based on an old project. Same circuit (almost) but put to a different use.

I have been planning an update to my oscilloscope project. The tube drivers (ECC81/12AT7) and the 1200 Volt PSU I am 100% happy with, but an oscilloscope needs a good sweep circuitry and a good trigger. Unfortunately I need an oscilloscope to develop this!!

Anyway, the tube/transistor scope is (sort of) working, back in Sweden, but I am not at all happy with it. Instead of just planning loads of stuff I have decided to make the homepages my lab-book, and document my thoughts. I have also created a PCB drawing. You can find the project at theis link:

http://sm0vpo.altervista.org/scope/oscilloscope-timebase-digital.htm

It is ridiculously simple, but there are some important points to consider. If you can read them and give me any comments, suggestions or ideas then I would be really grateful. If you think it will fly, then please say so. Please post any technical comments or suggestions to the questions/technical board (and not this homepage news board).

Very best regards from Harry - EA/SM0VPO (rig-less)

(PS - I do have ECHOLINK and I have had a few contacts on it during the last couple of weeks.)