Hi Listmembers!
The following is a discussion of a nice technique for data
presentation. All it needs is a digital camera and software you probably
already have. It produces a graphically striking view of the "hot spots" on
a circuit board. The view can be printed or emailed to share the results.
I don't claim any technical originality or new insights. This is
just an example of what you can do with resources you may already have. I'm
only going to post the first couple of paragraphs, without the JPEG files,
to this list. If you would like the complete text, plus the four JPEG
files, just email me and I'll send you the complete 2 MB MS Word text and
picture package.
++++++++++++++++++++++++
I recently did a study for a division of our company which produces
revenue collection devices (ticket machines, card readers, turnstiles, fare
boxes, etc) for the rapid transit industry. This particular EUT has a
stylish 18" tall fiberglass housing and will be mounted in the passenger
area of a bus. The EUT is equipped with bright LED indicators, a large
liquid crystal display with a fluorescent backlight, a microwave data link,
an infrared data link and a 13.56 MHz transponder (for powering and
interrogating a "smart card").
This EUT had a large number of emissions throughout the 30MHz to 1
GHz range. The case was non-conductive, so every circulating RF current was
radiating nicely. Ferrites added to the only cable (the 12VDC power input)
didn't solve most of the emanations.
I determined that almost all emanations originated on the liquid
crystal display driver board at the front of the EUT. This board had been
purchased from a non-local vendor. The question became one of how to convey
the noisy RF condition information to the program engineers and the display
board vendor's engineers.
The first thing I did was shoot a color digital photo of the driver
board.
Ed Price
[email protected]
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
858-505-2780 (Voice)
858-505-1583 (Fax)
Military & Avionics EMC Services Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis
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