EEVblog
ฝัง
- เผยแพร่เมื่อ 14 พ.ย. 2013
- Dave demonstrates how to do some basic in-house EMC Pre-Compliance conducted emissions testing on a DC powered product using an open source hardware Line Impedance Stabilisation Network (LISN) box, and a low cost Rigol DSA815 spectrum analyser
amzn.to/1b1aPJH
www.tekbox.net/open-hardware/t...
NOTE: As stated on the product page, this product and technique is for DC powered products only, it is not to be used for the mains supply.
EMC Test Facility: • EMC RF Anechoic Test F...
Forum: www.eevblog.com/forum/blog/eev...
EEVblog Main Web Site:
www.eevblog.com
EEVblog Amazon Store:
astore.amazon.com/eevblogstore-20
Donations:
www.eevblog.com/donations/
Projects:
www.eevblog.com/projects/
Electronics Info Wiki:
www.eevblog.com/wiki/ - วิทยาศาสตร์และเทคโนโลยี
Every time he starts with "Hi!". Every single time, his enthusiastic intonation makes me smile! :D
Awesome video. I do EMC testing for a living, was surprised to see this in my subscription box. We divide our EMC tests into 2 main groups: "Ground Plane" and "RF" testing. The RF stuff I do includes this, Conducted Emissions, as well as Radiated Emissions, Conducted & Radiated Immunity, Click (which is a form of conducted emissions testing using a specialized click tester), Harmonics, and Flicker. We use an anechoic chamber for most of this testing with filtered power feeding the chamber.
The "ground plane" side performs tests like: PQF, EFT, ESD, and Surge. All of which are meant to test the electronics robustness to undesirable voltages and currents entering the product through various paths.
There's never a shortage or things to learn or standards to read with EMC testing. Fun stuff.
Could I pick your brains Winter?
I would love to build some high frequency antennas and boosters ranging from 890Mhz - to 30Ghz range. For personal point-to-point data transmissions towers. We need high data throughput for free! I want to build a wireless mesh, by the people for the people.
Could you recommend any of your favourite designs with dimensions and materials? It seems like some serious precision work and without the correct test tools. Currently not able to for pay RF chamber testing time but I'm always willing to learn from my mistakes, as this is just a hobby of mine.
As I understand it, to avoid disturbance to other services on particular spectrums government authorities allocates/ "sells out" them to large corporate companies. Last time I checked the air we breath is free :)
Thank you very much in advance!
-Trev
Tradie Trev
The air you breath is free, but when you start interfering with the GPS signal of the airplane trying to find an airport in whiteout conditions, you pose a serious safety threat. Dont be stupid. If you interfere with someone's cell phone, its annoying, when you interfere with stuff like GPS, you can get someone killed.
That said you can create mesh networks from off the shelf equipment. Creating your own high frequency, high efficiency antennas and TX/RX equipment is not a small trivial task. It will require expensive equipment and a tremendous amount of knowledge. You may want to brush up on your Maxwell's equations.
Tradie Trev
EMC testing and Antenna design are very different areas of expertise. I use antennas in my work but we do not design them. Also, working up at 30 GHz frequencies requires incredibly high precision in terms of board design/layout and component selection. Creating antennas and circuitry at frequencies that high is way beyond my, and most people knowledge. It really takes an RF design expert to make something that operates at 30 GHz.
Best of luck & stay safe.
theonlyari Hadn't planned on killing anyone or disturbing other vital services, I'm not that evil :)
It's quite amazing the amount of engineering that's gone into mobile phone towers, I know it possible to build such high through-put networks as many country towns rely on their microwave links as a means of communication.
10 years later: what is good bang for the buck solution for EMC pre-compoliance tool today? :) Today talked with R&S representative and 5-6k euro for FPC1500 + EMC module i little steep for one man startup company 😅 at least for sub-GHz RF product prototyping… thanks in advance! :)
This is not taught in school and therefor EMC is considered black vodo magic for many people. Excelent video!
+rovfitta ya I never really understood why they didn't teach it, we barely even touched spectrum analysers!
" the University of applied Sciences in Amsterdam a rigorous EMC course is compulsory, for ee students.
Rigol have a reasonable piece of EMC test software which is worth using.... Incidentally I tested the Rigol DSA815 against a PMM9010/30, a Keysight N9038A and a Rohde & Schwarz ESIB26 on Conducted emissions from LED Lighting in a fully screened room and found the results were functionally identical. just a DB/uV here or there different. The real difference is the time it takes to make the QP sweep!
#555 will have to be dedicated to the humble yet trusty 555 timer!
Excellent tutorial with detailed explanation! Thankyou very much .
Thanks Dave! A Pre-Compliance Radiated Emissions Testing video would be cool to see some time. I wonder if others would be interested in this too...
The EMC legislation in Australia is so vague..
"This will be just a relatively quick followup video" - nearly half an hour :D
You´re the best Dave! I really enjoy your videos! thanks...
Great video Dave.
This is very informative. Although sometimes Ferrite cores dont work. Sometimes an inline filter has to be added. I like your reaction when it does bring it under the limit though. "Beauty" :)
Excellent tutorial Dave, keep them coming. I am at that stage now I need to get my product EMC compliant and this helps to get some perspective, will have to get myself a Spectrum Analyzer for sure!
Now, if my product has got for example audio line input and output, would I still be using the same kind of test box in series to measure conductive EMC? I think it would be MUCH appreciated if you did some more videos on compliance, KEEP THEM UP!
Hey Ronald, I'm currently at the same stage you were 6 years ago.
Could you please share your experience on how you went through pre-compliance in the end?
Our product is a 5V USB powered microcontroller device, wondering how I can test that for pre-compliance having a spectrum analyzer. Many thanks.
Good video, well done !
great video
Very Awesome video!
Dave, are you sure that part of that low Khz noise may come from your switching PSU?, won't it be better to test this things with an analog linear type?
Hi Dave, I'm wondering why you set the internal Attenuator to 0dB Manually?! The risk of killing the Input of your Analyzer is rather high by doing that. The dynamic of the Rigol is not that great, but it should be enough for this. Normally I'd use at least 10dB internal and a dedicated external 10-dB Attenuator as a protection for the receivers.
Cheers Dave :D
LOL!
I have never seen anyone use a common-mode clamps like that (differentially) :D
Excellent tutorial Dave, I was wondering why there are some rigol equipment with a blue logo. I'm about to buy a Rigol DSA815TG spectrum analyzer and it has the blue logo, why?
Switched power supplies are a real bitch. Especially when you are doing RE, CE, CS, and RS for FAA DO-160... because they dont allow you to put ferrites on your power lines to make noise disappear. Great tutorial, more EMC stuff!
Any suggestions for eliminating noise from a BLDC cooling fan in an RF circuit?
Do you connect the ground plane to the earth?
Why not use the preamplifier too?
When did you get that DSA and why haven't you taken it apart?
I have.
*** WARNING ***
This LISN and the setup is totally incorrect for mains powered devices (CISPR 22).
This LISN designed for testing in accordance to CISPR 25 (Vehicles, boats, internal combustion engines). Probably only DC supplies.
The title of the video is EMC Precompliance Conduction Emissions Testing. It's supposed to be a quick and dirty check you make before you go to the actual test house to have the unit officially tested. Hence the term "precompliance".
Chuck Sampson Yes, definitely. So wrong setup and assumptions shall cost a lot of money, time and effort.
This 'low end' spectrum analyser is over 2 grand! Some of us don't have rich daddies.
Is it possible to use an oscilloscope with the LISN device, instead of buying a spectrum analyzer?
Old tektronix Oscope like TDSxxx/C/D serie do offer FFT's so spectrum analysis.
"...but I would love to see a mini-series on designing and etching boards at home if you are into that sort of stuff."
Unfortunately, he is a pro :(
There are problems with the eevblog forum, or it is just for me?
The forum appears to be unavailable at this moment.
EEVBLOG!
Explain pk, quasi, etc!
3 types of measurements are common with this testing: Peak, Average, and Quasi-Peak
Peak is exactly what it sounds like - the highest level measured at that frequency. It gives no indication of how strong or persistent the signal really is only the maximum value measured during the sweep.
Average is also pretty self explanatory - it is a value that reflects the average level of the signal at that frequency. If the signal at a certain frequency is very common you will have a higher average than if that signal were intermittent, or infrequent.
Quasi-Peak is harder to explain and somewhat like an average but calculated differently.
Taken from an Agilent Technologies website:
(quote)
"Most radiated and conducted limits in electromagnetic compatibility (EMC) testing are based on quasi-peak detection mode. Quasi-peak detectors weigh signals according to their repetition rate, which is a way of measuring their "annoyance factor." They do this by having a charge rate much faster than the discharge rate. Therefore as the repetition rate increases, the quasi-peak detector does not have enough time to discharge as much, resulting in a higher voltage output (response on spectrum analyzer). For continuous wave (CW) signals, the peak and the quasi-peak response are the same. The quasi-peak detector also responds to different amplitude signals in a linear fashion. High amplitude low repetition rate signals could produce the same output as low amplitude high repetition rate signal.
Quasi-peak detector readings will always be less than or equal to the peak detection. Because quasi-peak readings are much slower, (by 2 or 3 orders of magnitude compared with peak) it is very common to scan initially with the peak detection first, and then if this is marginal or fails, switch and run the quasi- peak measurement against the limits.
For further information, please refer to Application Note 1328 "Cookbook for EMC Precompliance Measurements" literature part number is 5968-3661E."
(end quote)
Most, if not all limit lines that are defined by IEEE, FCC & CISPR will be Average and Quasi-Peak limits. Average and Quasi-Peak information is more telling of the true activity at a frequency than just the peak measurement. As far as I know Peak measurements are not compared to any limits for Pass/Fail criteria.
@@twomorestars app note does not google :-)
There's two CE marks - CE where the "CE" are close where the characters are almost touching = EU, "C E" where there's a gap (as this wall wart) is a made in China copy.
It's the opposite of what you said.
Is this google plus comments? (just testing)
Goddammit
La ast w foartenaspa ce este mai degraba faci un cest opening
C-C-C-C-COMBO Breacker
details, only TINY details XD (sorry for my nazi-grammar)
Does anyone have an old quotes for various types of EMI testing services that would be conducted at a laboratory that they wouldn't mind sharing with me? I want to get a rough order of magnitude feel for what an EMI facility charges for access to the lab and equipment, etc. I don't need the quotes and am interested in the $ figures. Every lab site is asking me to submit a request for a quote but I don't have a real job for them and don't feel right making something up and wasting their time. Seems awkward.
No teardown...😒😒😒
200V max? useless
You can make your own LISN with higher voltage parts, or just change low-voltage parts in that device.