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In official testing the power is normally supplied via an isolated AC-DC power supply, rather than a battery. I don't think the ESD gun will discharge if there's no path to ground. You'd need coupling planes, otherwise it will charge the DUT but you'd have to touch it with something that has a path to ground to create an ESD spark.

You are right. Thanks for noticing!

Yes, makes sense. I guess I wanted to see more sparks!

Afraid no, we didn't complete the series. I renamed the videos now

We use CST Microwave Studio for EM simulations, Keysight ADS / LTSpice for circuit simulations, and Altium Designer for the layout. We used all of them to design this prototype. In future videos I will try to explain the process.

​@@DrEMC-sf8rxThank you for your kind reply. I look forward to watching the video as well

It's powered from an ordinary IEC power extender via AC-DC adapter. You can see wires in the frame sometimes. The measured power consumption of the RIS surface is 2.2W, and of the whole system 6W.

Спасибо!

Yes, they do. But the pencil E-field probes that I also used in the video do not. Note that the E and H field distribution can be very chaotic in the reactive near field, so it's improtant not to rely on this 'measurement' for anything other than troubleshooting.

@DrEMC-sf8rx No, Actually I was asking about loop antenna polarizations 150k-30M) in far field for RE measurement as per CISPR 11 group 2 limits

@@vishvajeet7064 yes, they are as well. I just went back to check a 9 kHz to 30 MHz spurious emissions test report where we used one of these gigantic loop antennas - and yes we tested both polarizations. One measurement for front and one for side.

@@DrEMC-sf8rx helpful.Thanks.❤

Cheers, bro! I had a few very busy months, but going to resume regular uploads in 2025 😀

Perfectly explained as always ! Thanks a lot and have a successful year in advance...

@@emc1018 thank you! It means a lot to me :)

Hi, you can read about the general-case FCC requirements for unintentional radiators here: www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-B I will try to make a video to explain the differences between FCC and CISPR soon, there are not too many.

It's relative simple - you first select the right impedance, so that it's highest at the frequency that you want to reduce. Then, you select the adequate current rating which should be at least 2x the rated current. This also drives the size selection. That's about it, now of course how do you know the frequency you may ask? That's not trivial and requires simulation/measurement. So it's a good idea to have 0R placeholders on the PCB on each power supply, just in case you need it.

@DrEMC-sf8rx Is there any calculation for choosing ferrite impedance? Like frequency & emission level I can see in graphs but choosing impedance to suppress noise level to some db is tricky to calculate. Also, if increase wire turns in ferrite, how do impedance increase like in which ratio

@@vishvajeet7064 yes, there are calculators and field solvers available. For conducted emissions you can calculate the filter insertion loss in dB, which is pretty easy www.emisoftware.com/blogs/emc-analysis-calculate-filter-insertion-loss/

I think you outlined it the other way around. Basically, the difference between "REESS coupled to power grid" (electric vehicle) and "RESS not coupled to power grid" (not an electric vehicle) is the application of Harmonics, Flicker, EFT, and Surge testing. These tests are applied to electric vehicles with REESS only, because they are directly connected to the power grid (230VAC). Note that harmonics & flicker testing applies ONLY if the power grid is 230VAC. In countries where the supply voltage is different or if the supply is DC, harmonics & flicker tests won't apply. Hope it makes sense!

@DrEMC-sf8rx Understood! Couldn't outlined in best way like you did. Thanks. H&F only applicable if EUT connected to low public voltages (220V, 230V & 240V)

Yes! 22.5 dBm to be exact, minus the cable loss. It's defined in the module's product datasheet (Telit LE910 in this case). In the other video I showed how you can actually verify that with CMW500, which is important because the actual value may vary from one module to another, even from the same manufacturer!

Thanks for your interest. I hope so. The objective of the course is to give an overview of the route to product compliance for IoT products. It involves many aspects such as EMC emissions, EMC immunity, electrical safety, etc. These topics are not specific to RF, and almost never covered in university modules.

@DrEMC-sf8rx Ok thanks for the response, Do you talk about CISPR standards in the course? I believe these standards are more relevant to non IOT devices

@@AlbertRei3424 that's not at all true. The EMC directive is directly referenced in the Radio directive, hence all EMC standards (i.e. CISPR) apply to radio equipment.

@@DrEMC-sf8rx Ok thank you, so is this course useful for people designing non IOT devices?

@@AlbertRei3424 again, I hope so. Since, the vast majority of EMC tests are not specific to radio and only a few that are. What field are you working in?

In principle - yes, with MIMO, although there are multiple radiating elements, each transmit chain propagates from its source and so will satisfy a far-field condition regardless of the number of transmit chains, so I think it is valid to think about MIMO system as the sum of individual antennas. Having said that, a 2x2 MIMO in LTE will typically back off the power when transmitting on multiple chains in the uplink, i.e. if it supports 23 dBm on a single chain the dynamic power algorithm will configure to set the power control to 20 dBm if using 2 chains. So, we should be aware of this dynamic power adjustment with multiple transmit chains that takes place in MIMO systems. The TRP measurement with CMW500 will show that, however it can only do measuremens up to 4x4 MIMO in the uplink. So, if you need to measure something more advanced you may need to consider an upgrade.

Hi! Thanks for the interest. First of all, this video is about Railway EMC and the course I have is about Radio EMC. The exact specifications depend a lot on the product and it's hard to put down a specific number. On average, the cost of a non-radio product compliance in UK, I think is around £10,000 per product, including the testing time at the facility and the report. If a product is a radio product, the costs tend to double on average. All of the above assumes that the product passes all tests on the first attempt or with very few modifications. The more time you'll spend at the lab, the more it will cost, obviously. My role as of EMC consultant is not to test products at the lab, since each lab provides the unbiased personnel to run the testing. Instead, I focus on helping clients to get their products ready for the tests and help them fix issues that arise during testing, or in other words, to minimize the amount of time my clients spend in the lab. Lastly, my course and the videos on this channel serve only as a brief introduction and an overview of the topic. There's no substitude for practical experience. If you're thinking about starting your own company in this field, I would recommend to find a local test lab in Canada and spend some time working there at least part-time. It will help you to gain more experience and decide if it's right for you. Hope this helps, and good luck to you too!

@DrEMC-sf8rx Опыта работы с СВЧ аппаратурой довольно много. Попробовать на парт тайм устроиться в лабораторию-интересно. Но конкурентов не очень любят)))

@@anatoliilvov8658 своя лаборатория - это многомиллионная инвестиция (стоимость оборудования, помещений, аккредитации и проч.). Вряд ли вы как конкурент. Я по крайней мере для них точно не конкурент))

Cheers!

No, you do not need to repeat the test. You can read more here: www.etsi.org/technologies/mobile/4G

Hi! Any distance is fine as long as it's larger than the distance between the trace and the ground plane for it to act as a microstrip. Else, a coplanar waveguide calculation of trace impedance should be used

Great question! The value of the series inductor is determined by the Q-factor and the frequency range of LISN. As a result, it's standardized as 50uH for CISPR32 (domestic/industrial) and 5uH for CISPR25 (automotive). You can use an AC LISN to measure emissions on DC lines, but not the other way round. However, you'd have to make up your own wiring because AC LISNs typically come with AC plugs and sockets rather than banana plugs.

I don't see how that would be possible. RF power and sensitivity are measured on a modulated signal (i.e. GSM or LTE or 5G NR) and VNAs cannot modulate/demodulate signals.

I can see why this may be confusing. The harmonics apply to electric vehicles because they can affect the power station, which is external to the vehicle. It is not the same when we consider ESD, because ESD can only cause damage to the vehicle. The R10 does not care about the vehicle itself. It only cares about the external equipment and the safety of other road users.

Great question! Clause 6.10.4 of R10 details the reasons why ESD is considered out of scope. Reading it between the lines, R10 is focused on the safety of a moving vehicle and since ESD can only happen on entry/exit while the vehicle is stationary, this means that in the event of ESD no safety hazard can happen. So, it's out of scope. But for obvious reasons, most ESA manufacturers I worked with would not be satisfied with this answer. Then they would either apply ISO 10605 for automotive ESD or the conventional EN 61000-4-2. Notably, automotive ESD test levels are higher and go up to +-15kV contact, +/-25kV air. I believe, the Ford standard requires that as well as SAE J1113/13, so this is why EN 61000-4-2 is often applied instead, with +-4kV contact and +-8kV air. This tells the manufacturer that the product can handle some ESD, and doesn't require the manufacturer to go above and beyond of what's needed to get the product into the market.

why fix something that isn't broken :)

That's correct, thanks!

Hey, thanks! Afraid that's just how internet works - slow during the day, fast at night. Fibre optic is probably the best option in the market right now. en.wikipedia.org/wiki/Internet_bottleneck

Thank you!

😀

Great to hear! Enjoy the channel :)

Hmm, does the interference still occur when a laptop is powered from a battery supply rather than mains? Also, is the laptop connected to the plasma cutter in any way, i.e. RS232 or Ethernet? I'd expect a plasma cutter to produce a lot of conducted emssions, but not as much radiated.

​@@DrEMC-sf8rxI've tried it both ways, connected to power supply and running only off battery. The laptop is connected to the control board of the CNC machine via USB. I've tried running a ground wire from the z axis mechanism to the plasma cutter case. That didn't seem to help. Then I ran a ground wire from the z-axis mechanism to the case of the power supply next to the control board. That seems to help a little. Most people connect their control boards to older computers with metal cases via the parallel port. But I use a cheaper card (similar to an Arduino) and it doesn't have a parallel port option. Using an older computer with a metal case and a parallel port seems to be a key factor in reducing HF interference. It is also recommended to ground the cutting table itself to an outside ground rod. I haven't tried that yet. I recently picked up an optiplex 960 which is an older computer tower with a metal case. I also picked up a shielded USB cable to run to the board. I should get a chance to test out the new setup in the next day or two. From what I understand the torch lead from a plasma cutter acts as a large HF antenna. I'm thinking about buying some Faraday fabric and using it to shroud the work lead.

@@roberthosking7524 I think it's a lot simpler than you think. The interference is most likely conducting via the USB port that you mentioned. Try a USB isolator, such as this one - it should fix the problem :) hifimediy.com/product/usb-isolator/

​@@DrEMC-sf8rx great - I'll get back to you after testing and let you know how it worked. Thanks. I think you might be correct on this. When the machine was freaking out the laptop it was chiming with a connect and disconnect USB sound.

@@Hollywood4Fun yes, please do! It's always fun to debug these :)

Hey, a plane wave is an approximation that is designed to simplify mathematics. A true plane wave cannot physically exist at any frequency. However, if we sample a 15kHz wave from distance 2D^2/lambda with a small loop antenna, then it will look like a plane wave to us, due to the antenna aperture being much smaller than the wavefront. Hope it makes sense?

Thank you for your comment! :) EN 301 908-13 is specific to E-UTRA UE, while EN 301 908-1 applies to any equipment on cellular IMT network. This includes UE as well as BS and all applicable radio access technologies (2G-5G, etc.). As a result, the testing to EN 301 908-13 is more strict as its detailed in a very specific manner per TS 136 508. For example, the lowest channel bandwidths, 5 MHz and the highest must all be tested, while in EN 301 908-1 we simply can pick the worst case. That alone increases the testing time 3x times. There are other differences.

@@DrEMC-sf8rx thanks!! That's good to know that it is more stringent than version 1.

It's just under 4 hours. One week sounds about right, but don't try to watch everything in one day. There is a small quiz at the end and the certificate of completion for these who are interested :)

This course is tailored specifically for RF/IoT products, and designed to provide a detailed ovderview of: a) the scope of RF testing b) standards and c) test setups. It's suitable for beginners, EMC test engineers, and managers as I've deliberately limited the amount of EM theory and PCB-level design guidelines in this course.

thanks for the correction