Hi Group,
Does anyone know of any differences between 'SABS CISPR22' and 'CISPR22' if
there are any?
Thankyou.
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All the ground layers should be tied together. This board is probably dense
enough that the normal ground vias will take care of it but you will need to
check and see if more need to be added. The decoupling caps should take care
of current paths that pass from the power to ground layer.
Like
RF propagation in different environments is being studied
at NIST in Boulder Colorado. One scientist involved in this
is a Dr Chris Holloway. I am sure he can answer all your questions.
Best Regards
Charles Grasso
Senior Compliance Engineer
Echostar Communications Corp.
Tel: 303-706-5467
Fax:
Robert,
just a partial answer:
Wood will strongly reflect 2.5 GHz and higher frequencies. Grain orientation
relative to field polarization has an effect too.
Neven
Do some of you have a good feel for the propagation characteristics of 2.5
and 5 GHz radiation? I am curious about how they
Chris,
the return current (CMOS) will START at either power or ground (very
inappropriate term), depending on the transition. However, the return current
will flow in the adjacent plane under the trace. The question is: If it starts
flowing in power at one end of the line, how does it get to GND
Eric Ken,
Thank you for your reply on this matter. These items
are of a business and a personal interest. Since I don't
work in Diagnostic Ultrasound these days these modems
probably don't don't effect the product I work on these days.
(That aught to tell you something.) Our business needs
Ralph,
I have never found a preselector to be particularly useful for my
applications. My measurements have at times required filtering, however.
When I am measuring harmonics of a transmitter I need a high pass filter or
notch filter specific to that carrier frequency. If I need a lower noise
Do some of you have a good feel for the propagation characteristics of 2.5
and 5 GHz radiation? I am curious about how they interact with typical
environmental materials like walls, earth, furniture, plumbing, wiring,
foliage, etc. What materials are transparent, reflective, attenuating? Is
Chris,
and here is another 10-layer stack-up, if you can give up two of the four fast
signal layers. The improvement here is an extra power plane and the power
planes are close to the top and bottom of the board.
SIG SLOW, GND POUR
GND
PWR
GND
SIG FAST
spaceX space
SIG FAST
GND
Chris,
your stack-up is good I think it could be improved. The central PWR-GND is far
from the top and the bottom. You will therefore have more via inductance than
placing the PWR-GND near the top or the bottom. Figure 10 pH/mil- that gives
about 1/4 nH to get from the center to the top or
Chris
Return currents will flow in both the ground and power planes - depending on
whether the driver output is switching low or high, and where you have
multiple ground planes, return currents will want to flow along the path
offering least resistance - typically the adjacent plane.
Have a
I read in !emc-pstc that brian_ku...@leco.com wrote (in
tfsdo...@leco.com) about 'Measuring Current Inrush and Startup
Current' on Tue, 30 Mar 2004:
1. Is there a standard that shows how to properly measure Inrush Current? How
about Startup Currents from large motor devices?
IEC/EN 61000-3-3
List Members:
I extend my appreciation, and admiration, for the many helpful responses to my
posting. These included not only postings, but also telephone calls which were
equally helpful.
While some responses concentrated on the loop antenna question, others
addressed the use that I have,
Greetings,
1. Is there a standard that shows how to properly measure Inrush Current? How
about Startup Currents from large motor devices?
2. For products that have a complex current draw over long cycles (maybe 2
hours
long), is there a measuring device that will simply monitor the AC line and
Reminder: The Intent to present and topic for your paper to be presented at
the 2004 IEEE SYMPOSIUM ON PRODUCT SAFETY ENGINEERING is to be e-mailed by
April 1, 2004, so time is running out. You have only a few days left to come
up with a topic and let us know your desire to present it. See
I have a 10 layer board with a stack up similar to that of Henry Otts articles
http://www.hottconsultants.com/techtips/pcb-stack-up-1.html
http://www.hottconsultants.com/techtips/pcb-stack-up-5.html
The stack up is
Signal (low-speed signals)
Gnd.
Brent DeWitt bdew...@ix.netcom.com wrote (in JFEKIIBLAHFLFLAPJDMDKENK
egaa.bdew...@ix.netcom.com) about 'What is in the position of the
ferrite core?', on Tue, 30 Mar 2004:
I just wanted to pitch in that Don's rather complete explanation of the
reality of ferrites on cables can also be viewed as
Bill et al,
IMO there is no easy answer to the problem of one area of test
provoking design changes affecting another area of test. A diverse
product line, such as individually sold PC cards and a line of
complete systems, would call for a different approach as needs demand
(often cost
Always do all Emissions testing first.
Followed by EMC testing.
Then Safety is last.
Regards, Doug McKean
_
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