Best oscilloscope choice?

[TinselKoala]

This is not an easy task, to take an image, and transform it into curve, which then can be used for calculations. I tried to find a software which transforms an image into such curve, i couldn't find. I tried to transform the picture in gimp, the difference of gaussians, etc, give an outline of the trace, two lines, but none are one pixel thick, and it is impossible to eliminate all the background dots. Thus such image cannot be used for calculations. So still it has to be done manually. Like load the image to gimp, then create a transparent layer, and draw to it one pixel dots. Then save that layer as xpm, which then can be converted to a table of numbers, and then some curve fitting program can be applied to it. There are many these. This method can provide very accurate results, and very nice graphs, but it's quite a work.

So i still stick to this manual drawing with gschem, mostly quite rough approximation is enough. Or when one wants to do it better, one may do it with inkscape or such, where i think too it is possible to add a transparent layer, and save it hopefully in some very simple vector graphics format, which then can be used for calculations, or then as a data for curve fitting.

Now does anyone understand what i'm talking about?

I certainly do. Back in the "Ainslie" day, I demonstrated how to do this process manually from a good photo of an oscilloscope trace. It is very tedious, takes about 4 hours to process a single image that way. But the results are accurate enough to be able to make valid conclusions.
I also used another technique to determine areas under a curve using pixel counting.

Now, of course, thanks to the generous donations of some forum members, I have an oscilloscope that does this math integration automatically for me.

[conradelektro]

I got this scope (UNI-T UTD2102CM):

https://www.reichelt.de/Oszilloskope-Spektrumanalyser/UTD-2102-CM/3/index.html?ACTION=3&GROUPID=4044&ARTICLE=123971

Is this a good scope?

I would appreciate comments from the experts.

I bought it mainly because it was easily available in my part of the world. The price measured against it's capabilities was reasonable. And it is totally modern and can also be connected to the PC via USB. So, it is a fully functional stand alone scope or it can be handled like a PC-scope with a program running on a PC.

It can also store images on a USB-stick. Funny enough, the capacity of the USB-stick should not be more than 8 GB, otherwise the scope behaves strangely when trying to store an image file on it. It seems to be the supported file system.

One can argue, that the knobs and keys are not as rugged as on highly priced scopes (e.g. from TEKTRONIX).

When I looked (about three years ago), a very good scope would have costed EUR 1500.-- and more.

And yes, it is a very steep learning curve to use a scope properly. But the modern digital scopes are more forgiving than the older analogue ones. Specially the storage capabilities are very helpful. Also the mathematical functions help a lot.

The scope becomes outdated if looking at fast computing equipment. Even microprocessors are running now beyond 1 GHz. One needs 32 channel logic analysers or mixed signal scopes (12 GHz sampling rate)  to see what is happening on a 3 GHz bus:

https://en.wikipedia.org/wiki/Logic_analyzer

Greetings, Conrad

[Paul-R]

Back in the "good old days" we would tape some tracing paper on the scope screen, transfer the scopetrace with a pencil, then cut out the waveform areas carefully with scissors and then weigh them on an analytical balance. This method can be surprisingly accurate if you do a little calibration testing beforehand.

Its a bit Barney Rubble, TK. Try a planimeter. Somewhere, there is a DIY planimeter page.

[Nink]

I had a 200Mhz Tektronix 475 about 20 years ago I left back in Aus.  Looking to buy a scope and the 475's seem to be selling ~ $300 US on ebay without probes and  that seems reasonable .  Is anyone still using these,  there seems to be a lot of them on the market but I didn't want to buy something that fails 2 weeks later, overheats, knobs break etc. Anything to look out for when buying one, any models, years to stay away from. Was thinking a 475 (200MHz, 2mV/div)  or 475A (250MHz,  5mV/div). 

[ayeaye]

The thread about how to measure power with analog oscilloscope is now there  http://overunity.com/16911/measuring-power-with-analog-oscilloscope/#.WAFXS7Np_iY . For using analog oscilloscope for overunity experiments, it is absolutely essential to use some method to measure power with these oscilloscopes, no matter what are the shapes of the signals. One may say that doing it in any other way than pixel counting, is "not professional" or whatever, but the same transforms of the picture of the oscilloscope screen have to be done also for pixel counting. So if one thinks that it necessarily has to be done by pixel counting, then please add to that thread the details of how to do it by pixel counting.