[SI-LIST] Re: Difference between conducted and radiated emission ?
- From: "Yang, Long" <long.0.yang@xxxxxxxxx>
- To: Ravinder.Ajmani@xxxxxxxxxxxxxx
- Date: Thu, 24 Apr 2008 18:01:01 +0800
In my understanding, conducted emission is inside conductors, while radiated
emission is outside conductors,
and conducted emission and radiated emission can interchange to each other
if some conditions reach.
In electro-magnetic theory, there are two types of current, conductor
current and displacement current.
Current conservative law is sustained by the displacement current discovered
by Maxwell.
Just for your concern
On Tue, Apr 1, 2008 at 12:16 AM, <Ravinder.Ajmani@xxxxxxxxxxxxxx> wrote:
> Hi Junfeng,
> Your question is more appropriate for the EMC Discussion Group. However
> since I wear both the hats, I may be able to give you an answer.
>
> The main difference between Conducted and Radiated emissions is in the
> frequency range. Conducted emissions are measured off the power cord of
> your system between 150 kHz and 30 MHz. Radiated emissions are measured
> from 30 MHz to 1GHz and higher, depending on the highest frequency being
> generated in your system.
>
> The main causes of conducted emissions are the switching power supplies,
> and low frequency digital circuits (which clock below 30 MHz). The modern
> cores run at hundreds of MHz and even GHz, so emissions caused by digital
> switching will not show up as conducted emissions. The core switching
> will cause radiated emissions, which can couple to the outside world
> through PCB traces, or common-mode coupling from Power and Ground planes.
>
> Regards, Ravinder
> Server PCB Development
> Hitachi Global Storage Technologies
>
>
> Email: Ravinder.Ajmani@xxxxxxxxxxxxxx
>
>
>
> "jun feng" <junfeng.zhou@xxxxxxxxx>
> Sent by: si-list-bounce@xxxxxxxxxxxxx
> 03/31/2008 04:17 AM
>
> To
> si-list@xxxxxxxxxxxxx
> cc
>
> Subject
> [SI-LIST] Difference between conducted and radiated emission ?
>
>
>
>
>
>
> Hi,
> Can anyone tell me the difference between conducted and radiated
> emission,
> especially for digital circuits ?? For instance, inside a large size
> digital
> core what is responsible for the conducted and what is for radiated
> emission
> ?
> regards,
>
>
> Junfeng
>
>
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