In-band interference of 4700MHz of CE certification test kills the UWB-ch3 link

Hi,

Has anyone else met the same problem concerning a new CE-certification test EN 302 065 – 2 V2.1.1 Clause 4.4.3. /EN 61000-4-3 / 9.2.1 .

Our DW1000 system works at UWB-ch3 (4,25-4,75GHz) and this new certification test procedure includes a transmit of a sinusoidal continuous wave 4700Mhz, -53dBm at EUT interference, which kills the link and test FAILs.

By our certification house mentioned this new test is added because of a new regulated spectrum allocation for PSME (Program Making and Special Events) equipments (media production microphones?) at 4700MHz. Anyone else met the same test and passed ?

BR; Pasi

Hi @ikopas
Im not a certificating expert but the
EN 302 065 – 2 V2.1.1 Clause 4.4.3 refers to Receiver interference handling and that is not what you are describing.

However for certification does not make any sense to testing transmitting continuous wave (CW) at 4.7Ghz - as there is absolutely no relation between this wave and the UWB packet. The CW can be only used for xtal trimming - that is almost the only one purpose of this mode. The second one is to observe some unwanted noise in this signal that could point to some powering issues.

Cheers,
JK

Thanks for the comment JK !

You are correct, EN 302 065 – 2 V2.1.1 Clause 4.4.3 refers to Receiver interference handling.

I could clafify more: Our DW1000 system works at UWB-ch3 (4,25-4,75GHz) and this new test includes a portion where an external transmitter transmits 4700Mhz interference signal, with power level of -53dBm to the EUT (there are optional interference types and our test house did choose continuous sinusoidal type) . As a result of this interferer the UWB link is cut (even EUT pair is at distance of 2m) and test FAILs. Only data related to this RX-sensitivity issue is on DW1000 data sheet : Figure 3 : RX Interferer Immunity on Channel 2 , it is only of ch2, but if the behaviour is close to similar on ch3, interference is strong enough to cut the link (?) . If it is a fact, then the next question would be: Is if this test is relevant an/or mandatory ?

Hi @ikopas
still Im not an expert here. You should talk to you Notified body that CW test for UWB device does not make any sense. It is even that big nonsense that it even does not worth to talk about it 8-)). UWB device uses 500MHz channel bandwidth - it uses all the spectrum not just the ultra narrow band that your test house wants to test in CW. There is absolutely no correlation between CW mode and the normal operation (except xtal offset).

As far I can recall in the CW mode you cannot control the “transmit” power - this is purely for debug purposes.

Im looking for some association and this one comes to mind (it is not that accurate as UWB cannot transmit over CW). Imagine you have a river (wide one) with nice smooth flow slow 10m3/s . And now some one come to you and told ok for passing the test you must maintain the smooth slow flow, but you must use drinking straw as a pipe. Obviously it is a total nonsense. :wink:

Im not familiar with all details, but it is possible to even certify it in EU/US for CH3?

Cheers,
JK

Hi @leapslabs JK !
By our certification house this new test (included in harmonized RED standard) needs to be passed to get CE label. The reasoning for this 4700MHz external interference test is spectrum regulation which allows PMSE (Program Making Special Events …? wireless microphones etc…?) use on 4700MHz band. It is ‘funny’ that we haven’t found any real devices to use that portion of spectrum. So, really eager to hear if any one has recently passed CE certification with UWB ch3 ? Pasi

Hi ikopas,

Assuming you are doing a CW interference test while DW1000 devices communicate 3dB higher than the sensitivity level and inject unwanted signal to the system by using a combiner. If this is the case, the In-band blocking level of DW1000 is 30dBc resulting in the best case scenario is with -93dBm sensitivity. In this case, DW1000 survives with the maximum interference of -60dBm CW in-band signal. Therefore, there is no way to pass this criterion, if my assumptions are valid.

Regards,
Emre

Thanks @eozbas / Emre !

By reading your comments,the Table 5 of datasheet and calculations, it really looks impossible to pass this test. Very interesting questions remains: Has anyone passed recently harmonized RED UWB test for CE marking on UWB bamd ch3 ? Our system passed those some years ago, but this test wasn’t on list at the time.

Br, Pasi