That's interesting. The change from 50 to 60 Hz would change some input
components and that could effect the input impedance and hence the
conducted emissions signature but the voltage, especially if its a well
regulated and filtered supply should be invisible. The components that
radiate at that point are all of the secondary 5 or 3.3 volt oscillators
and stuff. They shouldn't even know the difference in the input voltage.
If using a switcher power supply it seems even more odd. The input
voltage is rectified and then chopped to "#$@ then more regulating and
filtering stuff happens. Then it hits the electronics.
Anybody else see this and have an idea why it might. I may be living in
a fools paradise here.
Gary McInturff
Packet Engines
-----Original Message-----
From: hmellb...@aol.com [SMTP:hmellb...@aol.com]
Sent: Monday, July 06, 1998 11:16 AM
To: dwight.hunnic...@vina-tech.com; emc-p...@ieee.org
Cc: eric.lif...@natinst.com
Subject: Re: Ce versus FCC
I have encountered certain European agencies requesting that not
only are the
conducted emissions required to be performed at 230V 50Hz but
radiated
emissions as well. I agree that for conducted emissions it may
make a
difference but I have not seen radiated emissions change when
the power source
is changed from 60 to 50 Hz (while keeping Voltage the same). I
did, however,
see recently a product change emissions when the voltage was
changed from 120
to 230 V. And, it did not matter if it was 50 or 60 Hz, only the
voltage was
significant. Go figure!
Hans
