Harvey,
Thanks for the validation on the video. I'm glad someone with a good eye
took a look. When you said "So your 1 Khz calibrator requires a decent
frequency response to (gasp!) 10 Khz," are you saying that a 100Mhz probe
won't work as well as a 10Khz probe when reading off the calibrator?
In the video, did you notice the fluctuation in frequency? It wasn't
sitting on exactly 1Khz. There's a bit of back and forth movement. Is that
normal and if not, what's the fix (not that I desperately need to fix
that.. but it'd be good to know).
Thanks.
toggle quoted message
Show quoted text
On Sun, Jun 9, 2019 at 5:37 PM Harvey White <madyn@...> wrote:
Very rough rule of thumb on square waves. A "decent" square wave
requires response to about 10x the fundamental frequency. (it only has
odd harmonics). So your 1 Khz calibrator requires a decent frequency
response to (gasp!) 10 Khz.
Still, the frequency compensation on most adjustable probes is decent
enough when done at 1 Khz. For other frequencies and the like, the
"flat top" of the square wave will likely be insufficient. That also
varies per probe. The P6015 high voltage probe has at least six or
seven separate adjustments for frequency response and flatness.
Normally, though, what Tek did is to optimize pulse response over
flatness of frequency response.
Video looks good to me.
Harvey
On 6/9/2019 1:29 PM, David Berlind wrote:
As I await all your answers, I started with page 1 of the manual this
morning and am liking the functionality. Compared to my initial
quick-plug-it-in see if it works the other day, things went much
better. The first thing I did was a factory reset (following the
manual's instructions of course). This may have fixed a few things.
Working with the probe calibration signal, here's a video of what I
observed after selecting some measurements for display. I'm using
some100Mhz probes at 1x.
On June 9, 2019 11:42:15 AM "Stephen Hanselman" <kc4sw.io@...>
wrote:
I don¡¯t have a lot of knowledge but two things. In the 540, 540A,
540C, etc the ¡° ¡° and ¡°A¡± speak a different HPIB language from the
¡°B¡± and ¡°C¡±. If a lab says calibration for $300 they ¡°may¡± hook it up
and make sure the readings are close but not much else.
I don¡¯t know what a fully automated set could do, I do all my
calibrations manually with the Tek software. The 540B takes about 5
hours to do a good job. If you were close I say bring it by and turn
you loose on my software.
Regards,
Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
DISCLAIMER:
This e-mail and any attachments are intended only for use by the
addressee(s) named herein and may contain legally privileged and/or
proprietary information. If you are not the intended recipient, any
dissemination, distribution or copying of this e-mail and any
attachments is strictly prohibited. If you have received this e-mail
in error, please immediately notify me and permanently delete the
original and all copies and printouts of this e-mail and any
attachments.
On Jun 9, 2019, at 08:25, David Berlind <david@...> wrote:
Hi all,
After starting my oscilloscope journey with analog scopes for the
last two years and seeing some of what the digital scopes could do
(for example, maths), I had been watching my local marketplaces
carefully for a good price on a digital scope in working condition.
I recently picked up at TDS 620B for $85 and am now beginning the
journey of getting to know it. I will be posting video of its
behavior which I think may be in need of correction based on initial
observations.. and I am of course looking for advice. But I may be
wrong about that. I will work on eliminating other issues first
(configuration, line noise, etc.).
My first inquiry involves four questions:
1. I could not locate an online manual for the 620B. I found the
Technical Reference and printed that out. But in terms of the User
Manual, I could only find a manual for the 620A (could just be bad
Googling skills). So, I downloaded and printed that out. Now, I'm
trying to ascertain whether the 620A manual is for the most part
applicable (should have done this before killing a tree to print it
I guess) or whether the 620A is different enough from the 620B that
the manual doesn't apply. I've been looking for some way to compare
the two side by side (I found some differently formatted data and
specification sheets so apples to apples isn't perfect, but there's
some overlapping data to get some jist). But I thought it would be
prudent to toss the question out to this group because maybe someone
will just know and can summarize key differences and how that
impacts anything (usage, probes, etc).
2. I'll take any suggestions from you pros on great ways to get
started with this scope. Configurations to try. Shortcuts. Anything
that will fast-track my introduction to expert operation of the scope.
3. The 620B did not come with any probes when I purchased it. I
noticed from the 620A documentation that that scope originally came
with a 6139A probe which lead me into an exploration of probe
characteristics. That probe's specs appear to match the 500Mhz
capability of the scope. Over the last two years, I haven't thought
much about the probes themselves. Just been using what I acquired
along the way and things seem to work. So, in the spirit of rooting
out any configuration problems before needing to effect any repairs,
to what extent could basic probe differences impact behavior? For
example, I have some basic 1X/10x probes (which might not be rated
for 500Mhz) that work nicely on my 7603. What incompatibilities
could exist between these probes and the 620B such that I might get
unexpected/inaccurate behavior?
4. Wondering whether it might be best and faster just to have the
pros take a look at the scope, I have inquired with a local
calibration service as to the cost of a "tune-up." The estimate
just for calibration for was over $300 (way more than the cost of
the scope). It dawned on me that one option might be to pay someone
in this group to bring her up to snuff. This is for hobbyist work
(repairing amps, radios, etc) so it's not like I need a certificate.
Is there someone here who does that sort of thing?
Thank you.
David
