Measuring jitter with an oscilloscope - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: December 31, 2018, 11:26:38 am
content: I'd like to make some jitter measurements on an audio signal from my headphone amplifier with my oscilloscope (Rigol DS1054Z (hacked)).Is this possible, if so how would you go about doing it?

author: David Hess
author_rank: Super Contributor
timestamp: January 01, 2019, 02:08:29 am
content: Any oscilloscope can do that but what kind of jitter do you want to measure?

author: Rerouter
author_rank: Super Contributor
timestamp: January 01, 2019, 05:38:10 am
content: Well to begin confirming you have a jitter issue, a simple mask test will show most of your issues, output a fixed sine wave towards the upper end of your ampliers capability, e.g. 10KHz, and set up a mask that is quite narrow with 1 full cycle occupying the screen, any deviation in timing should then be flagged by the mask.

author: Bud
author_rank: Super Contributor
timestamp: January 01, 2019, 06:01:39 am
content: To measure jitter with an oscilloscope you need to know jitter characteristic of the oscilloscope, otherwise you will not know if you observe jitter of the signal or the oscilloscope. Knowing how bad rigol is about their master clock, chances are such measurements will make no sence on a rigol.

author: TheNewLab
author_rank: Frequent Contributor
timestamp: January 01, 2019, 06:06:49 am
content: Quote from: Bud on January 01, 2019, 06:01:39 amThis is what I would be concerned about. In my case..I suspect that I have so much energy flying about on my lab bench, no matter how much I calibrate my scopes. there still is not a steady signal. I just do not know how to isolate all of it, except the basics like AC power line

author: boB
author_rank: Frequent Contributor
timestamp: January 01, 2019, 06:12:00 am
content: You might try measuring a stable source first that you might be able to pretty much trust.Maybe a nice crystal oscillator, with specs if possible, but if you see that this clock is stable, then you might assume it's OKand the Rigol is OK. As long as your trust in jitter is better by some amount than what you are measuring, then shouldbe able to get a good idea of the DUT.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: January 01, 2019, 01:57:36 pm
content: Quote from: David Hess on January 01, 2019, 02:08:29 amHigh frequency 20 KHz sine waves.

author: tautech
author_rank: Super Contributor
timestamp: January 01, 2019, 02:00:27 pm
content: Quote from: drummerdimitri on January 01, 2019, 01:57:36 pmIncrease trigger hold off.

author: David Hess
author_rank: Super Contributor
timestamp: January 01, 2019, 02:11:31 pm
content: Test your Rigol first since they had a serious problem with sampling jitter in the past:https://www.eevblog.com/forum/blog/eevblog-699-rigol-ds1054z-oscilloscope-jitter-fix-testing/All of my old DSOs have jitter levels commensurate with the crystal oscillators I have tested them against which makes sense because they use crystal oscillators to control the sampling clock. It takes a high bandwidth oscilloscope to make meaningful measurements at low jitter levels like you would find between logic stages or between crystal oscillators; a 500MHz instrument will not cut it for this. Sampling oscilloscopes are good for this.For audio applications it is going to depend on exactly what you want to measure but any 100MHz or even slower instrument will reveal anything which matters. A phase noise measurement using an audio analyser would be more relevant.Quote from: drummerdimitri on January 01, 2019, 01:57:36 pmRight, but jitter over small time periods or long time periods? Due to limited resolution, an oscilloscope is more suitable for the later unless it has a really high timing resolution like a sampling oscilloscope.

author: 2N3055
author_rank: Super Contributor
timestamp: January 01, 2019, 03:20:43 pm
content: Quote from: Bud on January 01, 2019, 06:01:39 amOh my god not that again...They screwed up, you found it,you got your spotlight, they fixed it, old news, it's history...Your 5 minutes of fame passed.. Get used to it...If you want to shit on Rigol, do us a favor and search for real bugs in their new products (there are many, bugs and products) and help people get a better product for a price that is affordable..I can make a very long list of total screwups big names did but for some reason nobody is allowed to say Keysight is "shit" because they made a PSU that destroys equipment connected to it on power up ... It was silently swept under the rug, and only 6 months after there was magically an A version.... It took too much time to fix that, and it left bitter aftertaste. But Keysight did right by us eventually, and all was forgiven, apparently.And release history for MSOX 3000T is 27 pages long.. some of it new features but mostly bug fixes... Yet it's a fantastic piece of equipment. It is not that simple.And Keysight is not shit for mistakes they make, far from it. And neither is Rigol. Rigol is still a long way from it to be in the same league like Keysight (and questionable if ever) but entry level equipment from Rigol is good equipment in it's category.DS1000Z has no advanced features, it has slow UI, but it performs up to spec. No jitter.If you can prove that jitter is still there, please enlighten us. In which case I would stand corrected, and would publicly apologize.Otherwise, forever stop with crap fear mongering, please....It really doesn't become you. You seem to be wonderful engineer, with vast knowledge. Help us by sharing that. We would be greatly thankful. And respectful of you and your accomplishments.