Single shot capture on an Analog scope - Page 1
Forum section: electronics / beginners

author: Jetfixxxer
author_rank: Newbie
timestamp: October 29, 2016, 09:14:20 pm
content: I'm fairly new to scopes and use my infrequently to justify a DSO.I have a Instek GOS-620 and wondering if there is a way to capture a single shot signal such as switch. Search results only suggesting taking a picture of the screen. Not sure if there is an add on I can use to do this. .Copy of the manualhttp://phys.thu.edu.tw/~mengwen/exp-electronics/datasheet/GOS-620.pdf

author: rstofer
author_rank: Super Contributor
timestamp: October 29, 2016, 09:25:02 pm
content: As you suspect, the scope has no storage capability so you aren't going to get a one-shot waveform.It often happens that we need to rearrange our project slightly to produce repetitive waveforms even though the final product has no such repetition.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 29, 2016, 11:13:28 pm
content: Quote from: Jetfixxxer on October 29, 2016, 09:14:20 pmIf you just want toseethe switch operation,set your 'scope to "auto" triggering & let it "free run" at the longest time/cm setting you have.Turn up the intensity,&/or reduce the room lighting,& operate the switch.The CRT will probably have enough persistence to (just) see what you want.In the old days,people used a film camera in the "bulb" or "time exposure" setting to capture such waveforms.I have used a digital camera to capture normal CRT displays,but I've never worked out how to use "time exposure" with mine.(I really haven't needed to for screenshots,as my Tek 7613 is an analog storage 'scope).It should be possible,though.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 30, 2016, 01:36:19 am
content: Yes, it is not only possible, it used to be routine. After all, the manufacturers of the scopes did include a "single shot" sweep mode, didn't they? You might not be able to do it with a cellphone camera but I've done it many times using my Canon DSLR and my old Tex 2213a and HP180a scopes.It helps to have a stable mount for the camera and a remote shutter release. Select "single shot" sweep mode on the scope and turn up the trace intensity. Turn off the room lights. Set a long exposure with the camera in "manual" mode or use "bulb" mode so that the shutter opens and stays open until you let up on the shutter button. Open the shutter with the remote release, then make your DUT do its thing. The scope will do a single sweep. Then close the shutter. It will take some experimentation to get the optimum exposure settings and scope settings for your particular application. It is a _lot_ easier to do it with a DSLR rather than a film camera like we used to do!

author: danadak
author_rank: Super Contributor
timestamp: October 30, 2016, 10:39:46 am
content: Another approach is a recirculating delay line, google that. Probably notpractical for this problem.Another approach is to make a simple UP based digitizer. If you used a PSOCit has Vref, A/D, D/A, and memory, a simple low speed (1 MSPS) scopefront end could be made with maybe a very small number lines of code. Justa thought.Google "psoc oscilloscope". Most use an LCD for display, no reason you could notuse DAC and develop a trigger for your analog scope instead of LCD.Regards, Dana.