Siglent SDS1102CML: Trigger Offset - Page 1
Forum section: electronics / testgear

author: blf
author_rank: Newbie
timestamp: March 25, 2014, 01:39:27 am
content: I noticed some strange behavior with a new Siglent SDS 1102CML Digital Storage Oscilloscope while working on a school assignment involving Sinusoidal waveforms. For some reason, the waveform is shifted left by about 24us when in normal trigger mode, but centered while in single trigger mode.At first I thought that this may be due to inconsistencies in the generated waveform (I'm using an NI myDAQ), but then I figured that the waveform would be shifted up or down if anything.Is this a normal occurrence with DSOs? Is there something wrong with my unit? Or, rather more likely, could I be doing something incorrectly which might result in such behavior?Edit 1: Updated time unit from nano to micro.

author: Siglent
author_rank: Regular Contributor
timestamp: March 25, 2014, 02:34:10 am
content: Hi blf, I haven't got a repetition like what you said. Can you give us some pictures or videos to show your problem?If you want get a quick explain, you can send email to support@siglent.com. They will reply you in 24 hours.

author: pickle9000
author_rank: Super Contributor
timestamp: March 25, 2014, 02:49:43 am
content: Try turning on persistence to see if you have a jitter issue.

author: blf
author_rank: Newbie
timestamp: March 25, 2014, 03:19:32 am
content: Thanks for the quick replies. Here are a couple images depicting the issue. The first couple show the myDAQ connection and settings while the last 3 show the oscilloscope in both Normal Trigger and Single Trigger modes. I'm working on uploading a video. I'll edit with the link once completed.Here is the link to the video:http://youtu.be/hYaVNmL5xQENI myDAQ to Oscilloscope Probe connection (probably not useful)NI myDAQ Function Generator SettingsSDS1102CML Infinite Persistence Normal TriggerSDS1102CML Off Persistence Normal TriggerSDS1102CML Off Persistence Single TriggerEdit 1: Not sure why the images aren't displaying. This is the first time I've tried posting images to a forum. If you right click, you should be able to access the URL.Edit 2: Fixed images.Edit 3: Added Link to Video

author: pickle9000
author_rank: Super Contributor
timestamp: March 25, 2014, 05:24:37 am
content: @ blfYou win, the scope does indeed act as you say but it's not defective.I have an 3 year old version of the same scope and reproduced exactly what you where seeing. Mine has the latest software.What you can do is switch to a square wave, and repeat the test at higher frequencies. What you will see is a one pixel shift when doing the single shot. Basically it's just how the wave is being drawn and not related to a problem with the gear. The waveform is not being distorted in any way and that would be a fault.To your credit I never noticed this so that is a plus.Noticing how your equipment behaves allows you to use it more effectively. Although it's desirable to find test equipment that works to an ideal that is never the case. All gear has problems being able to identify them and work with / understand them is important.

author: blf
author_rank: Newbie
timestamp: March 25, 2014, 05:44:56 am
content: @pickle9000Thanks! I'm pretty new to working with hardware. I've been simulating stuff for a while now, but only really started playing with real hardware this year. I kind of had an idea that this was the sort of thing I could make note of and not worry too much about, but wanted to make sure just the same.