| Products > Test Equipment |
| Building my own scope |
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| balnazzar:
--- Quote from: tggzzz on October 20, 2022, 09:51:18 pm ---Provided the computer can take the samples at a mean rate that is higher than the sampling rate, all is well. --- End quote --- Mh. Not promising. |
| jasonRF:
--- Quote from: balnazzar on October 20, 2022, 08:33:21 pm --- Thanks. If I venture into it, that will be a very-very-long-term learning project, without expecting to get my actual working scope from it. --- End quote --- Yup. And as others have said, if/when it is finally working, it will almost certainly not compete with a new scope that you could buy with the money you spend on it. Going back to the beginning of the thread, I think it really is remarkable what $1000 can buy these days. Exactly what you want might not be available, but that goes along with engineering in general. Similarly, the exact parts you want for your scope project might not exist, or they may be unavailable (pretty likely these days) or too expensive for your project. You find creative ways to overcome challenges using the parts and test gear that you have access to. jason |
| gf:
--- Quote from: pcprogrammer on October 20, 2022, 07:44:54 pm ---A scope without a FPGA is certainly possible, but would not have a high sampling rate. Take a look at these little scopes made with a STM32103 MCU. Just 1MSa/s --- End quote --- The low-cost Hantek 6022BE uses an EZ-USB microcontroller to stream the ADC samples via USB2 to the PC. No FPGA involved. Sample rate is 48MSa/s, IIRC. Processing (incl. trigger) is done on the PC. |
| pcprogrammer:
There is one thing that is overlooked in this talk about a scope without a FPGA, and that is DMA. (direct memory access) It is possible to do sustained capture with it, but to do triggering on the signal will still require the processor to do a lot of work. With microcontrollers it still would not bring the high sample rates. No idea about the speeds that can be obtained with a modern PC. The cards of the company found by you, balnazzar (https://dev.alazartech.com/en/) also uses a FPGA and has lots of memory on the card to do the data capture. As a starting point for learning take a look here: https://www.fpga4fun.com/digitalscope.html It starts with the basics. Since you, balnazzar, did not comment on my last post it might be that you missed it. It provides lots of information you asked for. https://www.eevblog.com/forum/testgear/building-my-own-scope/msg4474414/#msg4474414 |
| alm:
There's always the possibility to do triggering in the analog domain using a fast comparator and timer. That would remove the need to do any real time calculations on the data. |
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