Electronics > Beginners
Is An Oscilloscope Practical
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KL27x:

--- Quote ---you don't want to invest in a scope unless it gets a reasonable amount of use, which is understandable.

--- End quote ---
In my own situation, the scope is a necessary evil. It gets an "unreasonable" amount of use. But when I need a scope, I need a scope. I think if you needed a scope, you would be the first one to know about it.

 >:D
VIO47:
Hi EEVblog Users,

I just registered on this forum and this is my first posting here. Hope this topic is the right place for my question, I don't think I should open a new topic only for a question.
I am a hobbyist in electronics and about one month ago I bought an oscilloscope SDS1202x-e. It is my first one and I hope it was a good choice, until now it helped me a lot. I did not intend to spend too much money only for hobby activities and I like very much the SPI and I2C decoding abilities included for free.
One question I have now, hope somebody can clarify here; the user manual is only summary and I couldn't find too much information. I have noted that the oscilloscope is able to show a correct rectangular signal shape up to about 2 MHz, at 4 MHz the shape is no more rectangular, the corners gets rounded, at much higher frequencies it shows more like sinus signal. Is this normal? Since the oscilloscope can go up to 200 MHz, I have seen a test at 250 MHz too, sinus signal of course, I was thinking it should work correctly with rectangular signal at frequencies higher than 2 MHz, at least the SPI frequencies. Anyway, on SPI the decoding works very well even with that distorted signal.
Fungus:

--- Quote from: VIO47 on January 09, 2019, 03:36:38 pm ---
One question I have now, hope somebody can clarify here; the user manual is only summary and I couldn't find too much information. I have noted that the oscilloscope is able to show a correct rectangular signal shape up to about 2 MHz, at 4 MHz the shape is no more rectangular, the corners gets rounded, at much higher frequencies it shows more like sinus signal. Is this normal?

--- End quote ---

It depends on the signal source, the way you connect the probe and the oscilloscope settings.

Three variables about which we have no information.
VIO47:
For this test I have used a ST32F103 board, signal was generated by PWM timer, test probes connected directly on the board pins, I have started with "Auto Setup" and then I tried to improve the shape using manual settings as much as I know now but without success. Maybe the STM32 is not able to provide a clean rectangular signal at higher frequencies? I am playing with STM since some time but I didn't have an oscilloscope until now.
exe:

--- Quote from: VIO47 on January 09, 2019, 03:36:38 pm --- I have seen a test at 250 MHz too, sinus signal of course, I was thinking it should work correctly with rectangular signal at frequencies higher than 2 MHz, at least the SPI frequencies. Anyway, on SPI the decoding works very well even with that distorted signal.

--- End quote ---

Be sure that 1) signal source can really produce square wave of that frequency 2) you have 10x probes 3) proper probe compensation 4) proper probing techniques.
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