Spectrum Analyzer Setup for Measuring EMI from USB Cables

Here I evaluate radiated emissions of USB cables with R&S FSC6 Spectrum Analyzer in near field, while also providing an overview of its technical features.
DISCLAIMER: THIS VIDEO IS NOT SPONSORED BY R&S
It's very important to test the quality of shielding in your digital cables because unshielded cables can easily fail the expensive radiated emissions test. USB cables should have 360 degrees shielding terminated continiously at the connector on both sides. It's the ultimate responsibility of the manufacturer to specify EMC compliant cables and this video will provide you with the knowledge of how to perform testing in near field in your lab.
There's a great application note ANP116 on Element 14 website that provides a comparative measurement between shielded/unshielded digital cables performed inside anechoic chamber:
community.element14.com/produ...
TIMELINE:
00:00 - Start
00:25 - Test Setup
05:22 - Frequency Control
07:10 - Amplitude Control
09:10 - RBW and VBW
11:29 - Sweep Time
14:26 - Trace Window
16:24 - Markers
18:39 - Features Overview Summary
21:28 - USB Cable Testing
28:30 - R&S Instrument View
31:03 - Closing Remarks

[@DrEMC-sf8rx]

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[@SP1-Poznan]

I have the same Spectrum Analyzer.
Using R&S InstrumentView software, you can compare up to four waveforms by clicking Get Trace and then Add Trace.
The power meter function is available by connecting an external USB sensor one of the R&S NRP-Z** family.

[@DrEMC-sf8rx]

I didn't think of that. Yeah that works! :)

[@willhaylock3769]

Would not an RF current probe, e.g. Fischer F2000 give you more repeatable measurements?

[@DrEMC-sf8rx]

Actually, I didn't realise they can go as high as 3GHz. Thanks Will, I'll see if I can get hold of one :)
To some extent, precision is not the most important thing here. But you're probably right

[@willhaylock3769]

@@DrEMC-sf8rx It's more about repeatability - as they they clamp around the cable they measure the current flowing on the outside of the screen, the current measured will have peaks and troughs as you move it along the cable but you can get a good feel for how good the cable is. You may be surprised that even a well terminated RG58 will have significant current on the outside of the braid as the braid does not give 100% coverage.

[@DrEMC-sf8rx]

@@willhaylock3769 yes, that makes sense. I could see some noise even on well shielded cables with near field probes as well
If I manage to get the Fischer probe, I'll put a new video up :)

[@mrechbreger]

There are really so many crap cables out there, you need to double check everything before buying it.
I saw manufacturers who are selling transparent shielded/braided USB cables but at the end did not connect them in the wire. Or some of them are using high resistance cheap wires inside...

[@ajingolk7716]

Hi i am a hobbyiest and i was wondering if it is possible to test EM r/a/t of some materials can you help me out thanks.

[@DrEMC-sf8rx]

Sorry, I don't understand the question. What do you mean by EM r/a/t ?

[@ajingolk7716]

@@DrEMC-sf8rx electromagnetic reflection/absorption/transmitance.
So i want to test some materials sheet for shielding from electromagnetic interferance and i think i can accomplish this with a spectrum analyzer if so how to do so?

[@DrEMC-sf8rx]

@@ajingolk7716 Ah! You'd need not just a spectrum analyzer, but also a signal generator and two wideband antennas to receive and transmit signals. But may I suggest that prior to making measurements, you may want to learn the EM theory and perhaps do some simulations in CST or HFSS where you got libraries of all common materials. This is a great resource to learn, in particular Topic 2 EM properties of materials:
empossible.net/academics/21cem/

[@ajingolk7716]

@@DrEMC-sf8rx great to know that a spetrum analyzer will help, for the signal generator can i use this board
EV-ADF41513SD1Z?