On Wed, Jan 22, 2025 at 6:54?AM Keith via groups.io <keith=
[email protected]> wrote:
Then for cal step 17 set the Siglent pulse gen to 500mV p/p (is that
supposed to be 0 to +500mV, or -250mV to +250mV? I used the latter),
I believe TG501 has positive-going pulses, but I don't think it matters for
horizontal calibration. It is perhaps safer to use positive going pulses,
as the scope under calibration might use a fixed DC level trigger.
It does matter for vertical calibration that you use GND to the indicated
level, though.
- Err, which screen? Is that the 'Delta REF / DELAY POS' control? Where
are they if they are not 'on screen'?
Next, "When markers are superimposed"
- Again, on what screen?
I only did this once, years ago, for my 2467, and I just don't remember the
details. Keep it in mind that the instructions are written assuming you're
using another analog scope as a bench scope, presumably that's why the
instructions on how to set up delays and such. With a digital storage scope
you don't need to worry about any of that, as you can just position the
trigger wherever you want on the screen, and the timing calibration on the
bench scope is not going to be in question.
As to what you're supposed to align, I just don't remember, I hope someone
who's done this more recently than I steps in here.
Assuming this is calibrating something to do with the B sweep delay,
presumably you ought to be aligning two copies of the timing marks.
If you look at A1U850A, you'll see that DLY_REF_0 and _1 can both make
their way to the B-sweep DR (delay ref) pin, so presumably this is
calibrating out something to do with the alternate delay paths?
If you have the case off, you can verify this by looking at the control
signal on U850A while sitting at step (jj). If it's alternating, then the
two delay refs are being alternately routed to the B-sweep delay ref.
Note that since the control signal is under microcontroller-control, the
switching will be quite slow, so maybe you need to bump the persistence on
your bench scope to see two instances of the time markers?
