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3
votes
2answers
53 views

RF Emissions Testing and Discovery of Hidden Undocumented RF Device

I would like to know is it possible to induce RF emissions (incidental waves (re-radiation) from a RF device that is not transmitting ? The purpose of this testing is discover whether there is a ...
0
votes
0answers
29 views

Is it possible to induce RF Emissions from a RF enabled Device (part 2)

Would it be possible to take a device anything such as a wireless router or a wireless video and induce unintentional RF emissions while the power is being supplied to the RF enabled device (baseband ...
0
votes
3answers
50 views

Is it possible to induce RF Emissions from a RF enabled Device

Would it be possible to take a device anything such as a wireless router or a wireless video and induce unintentional RF emissions while no power is supplied to the device ? Can you send it some range ...
4
votes
3answers
120 views

SIM900 Conducted Emissions Fail

I'm currently having trouble getting a product through EMC. Radiated emissions were comfortably under the limit, but conducted are failing badly. Here are the results: The noise appears to be ...
-2
votes
1answer
100 views

RF Emissions (Unintentional) [closed]

Hello can a device emit unintentional RF emissions when there is no power supplied to the RF embedded device such as a wireless router ? [UPDATE 1] YES when there is absolute NO power whatsoever ...
0
votes
0answers
52 views

Do I need to worry about FCC emissions when using PWM?

I have a AC-connected (though an adapter) unintentionally radiating device that runs a large DC motor (12v, ~6a continuous) under <10khz PWM control. Naturally, switching this large a motor ...
0
votes
2answers
47 views

Transceiver and RF Emissions (Unintentional)

My question is simply what is RF emissions (unintentional) and how does it relate to a device (such as a smart phone) which contains a transceiver or transmitter (baseband IC) ? Which part of a RF ...
0
votes
1answer
48 views

FCC Per Unit Factory Test For Intentional Radiators

Can someone clarify if each unit for an intentional radiator must perform factory emission testing or is this only required for a one time tst in an approved test lab? Is this tied to a specific ...
0
votes
3answers
125 views

Via fences or pickets important parameters for design

What is more important for EMI shielding effectiveness with respect to guard traces and via fences, the width of the copper trace that circles around the area or the distance between the vias to ...
0
votes
2answers
92 views

How dBuV value changes with distance?

I've got an emissions source that's designed to generate a peak at a certain frequency that when measured by an antenna 3m away gives a value of X dBuV. If the emissions source if moved closer to ...
1
vote
1answer
185 views

Can I cross the output inductor trace with input power line?

I'm attempting to learn a little more about SMPS design while referring to existing designs and posts such as this one: SMPS PCB Design Critic I'm implementing an AL8805 based constant current buck ...
5
votes
4answers
812 views

How to fix EMC problems for existing designs?

I'm going to be looking at a few products that have failed EMC radiated emissions testing and will need to apply fixes in order to make them pass (unfortunately, in these cases, two of the designs can'...
3
votes
1answer
184 views

LT1084 as Current control Regulator

I am using LT1084 as a current control Regulator. Circuit shown below Since the transistor Q2 is controlled by a PWM pulse so output voltage of LT1084 is varying as shown below Since it is used as ...
2
votes
2answers
160 views

Stray-inductance and capacitance of non-isolated heat-sink

I read an application-note that says the heat-sink (when not electrically isolated), is one of major source of EMI. Well I think this can be corrected at some point by good EMI filters and a good case ...
3
votes
3answers
576 views

Assessing and reducing EMI from PWM LED lighting

I need to run 50 individually dimmable LED fixtures on a pair of wires 30m long. Total load will be about 6A at 48V DC. I have to get power and control down a single pair, and AFAIK there are ...
6
votes
2answers
611 views

How good is coaxial cable?

My question relates to the accumulated AC voltage that will appear on the screen of a length of coax: If the cable is properly terminated at one end and fed with data (or any signal) at the other ...
0
votes
2answers
1k views

PWM controller to meet EMI/EMC regulations

I'm designing an application in which the current running into a load is controlled by PWM. A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
4
votes
2answers
2k views

EMI/RFI emissions and computer cases

I have designed a computer case (enclosure) for mini-itx motherboards. Its bottom and rear are made out of 2mm thick aluminium and the sides and top out of 4mm plastic (ABS). I'd like some advice ...
1
vote
0answers
100 views

FCC Pre-Certification Testing [duplicate]

Possible Duplicate: FCC and CE Testing / Failure Resolution I am looking to do some pre-certification on several boards. I know several members here are quite experienced in this area. I would ...