I work at NEC where we're developing embedded computer systems which are quite similar to wifi routers in a lot of ways. You wouldn't believe the amount of effort we have to go to in making these things meet EMI/RFI emissions standards. We spend months trying to shield out the crap which modern processors radiate all over the frequency bands. Even something as "simple" as USB is horrendous for emitting wide-band interference. USB cables act as excellent antennas, it turns out.<br>
<br>Some chips emit a lot of EMI and others don't. It's very disheartening to come up with a design, go through the multi-month prototyping and fabrication process only to find out that one of the chips you chose just happens to emit all sorts of crap and there's no way it'll ever meet emissions standards. That's something they don't mention in the data sheets let me tell you. Your only option then is to redesign with a different chip and cross your fingers that you'll have better luck this time.<br>
<br>Switching power supplies are a classic generator of EMI so like other people said the power adapter's a definite possibility. But I just wanted to point out that making any modern high speed digital electronics RF-quiet is harder than you might imagine!<br>
<br>Cheers,<br>Zik<br><br><div class="gmail_quote">On Wed, Dec 3, 2008 at 9:39 AM, Peter Buncle <span dir="ltr"><<a href="mailto:peter@nmc.net.au">peter@nmc.net.au</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial">I concur</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial"></font></span> </div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial">Peter</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial"></font></span> </div>
<div dir="ltr" align="left"><span></span> </div><br>
<div dir="ltr" align="left" lang="en-us">
<hr>
<font size="2" face="Tahoma"><b>From:</b> <a href="mailto:melbwireless-bounces@wireless.org.au" target="_blank">melbwireless-bounces@wireless.org.au</a>
[mailto:<a href="mailto:melbwireless-bounces@wireless.org.au" target="_blank">melbwireless-bounces@wireless.org.au</a>] <b>On Behalf Of </b>Tyson
Clugg<br><b>Sent:</b> Wednesday, 3 December 2008 12:15 AM<br><b>To:</b>
emdeex<br><b>Cc:</b> <a href="mailto:melbwireless@melbournewireless.org.au" target="_blank">melbwireless@melbournewireless.org.au</a><br><b>Subject:</b>
Re: [MLB-WIRELESS] Mitsu R100 (Asus 500g) causing
interference<br></font><br></div><div><div></div><div class="Wj3C7c">
<div></div>2008/12/2 emdeex <span dir="ltr"><<a href="mailto:emdeex@gmail.com" target="_blank">emdeex@gmail.com</a>></span><br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I
thought that as well, the interference would be waaay out of band...
but...<br><br>Do you mean the AC/DC plugpack? I've tried it with the
plug pack<br>still powered up, the R100 unplugged, and there is no
interference.<br>So it's the R100 unit causing the interference.
Something inside the<br>unit.</blockquote>
<div><br>Don't be so quick to jump to conclusions - it may be that the plug pack
generates RF noise under load only. You should try with another plug pack
(of same voltage and same/higher amperage/wattage) before asserting the R100 is
at fault. I would especially suspect the plug pack as most are low cost
switchmode circuits which typically switch at frequencies that would cause
interference on AM/FM radio. You can also try to find another device of
similar load to the R100 to power from the plug pack and see if the interference
remains.<br><br>Regards,<br>Tyson. <br></div></div><br><br>
</div></div><hr size="1">
Message protected by MailGuard: e-mail anti-virus, anti-spam and content
filtering.<br><a href="http://www.mailguard.com.au/mg" target="_blank">http://www.mailguard.com.au/mg</a><br> <br> <br></div>
<br><hr size="1">Message protected by MailGuard: e-mail anti-virus, anti-spam and content filtering.<br><a href="http://www.mailguard.com.au/mg" target="_blank">http://www.mailguard.com.au/mg</a><br>
<br> <br><br>_______________________________________________<br>
Melbwireless mailing list<br>
<a href="mailto:Melbwireless@wireless.org.au">Melbwireless@wireless.org.au</a><br>
<a href="http://wireless.org.au/mailman/listinfo/melbwireless" target="_blank">http://wireless.org.au/mailman/listinfo/melbwireless</a><br>
<br></blockquote></div><br>