Rocky Mountain Chapter EMC Society

Our last meeting was..a doubleheader.

Date : January 24th 2000

Location: National Institute for Standards and Technology (NIST) in Boulder Co. (Directions) Room 1107

BE SURE TO CHECK OUT THE PICTURES!!

1) "An overview of the C63 standards "

Presenter: Barry Wallen, Laboratory Director Criterion Technology. He currently sits on three of the C63 subcommittees. He has been involved with C63 activities for the last 8 years.

What we saw:  This discussion covered  a brief review of the structure of the committee and its subcommittees as well as a look at their current activities. There was something here for everyone, manufacturers, testing organizations, and designers. Barry also went into some detail in anttena calibration, alternate site calibration (no grandfather clause!!) and test issues being addressed by the ANSI committee. One particular item is a proposal for conducted measurements on cables - currently in CISPR22 3rd Ed and being examined closely by ITI TC5. This new requirement will dramatically increase test time and potentially add more cost to ITE equipment. These sorts of additions to standards exemplify why companies should participate in the standards making process.

2) "Where the noise starts - a discussion on PWB design"

Presenter: TJ Ritenour (EMC Compliance LLC)

What we saw:  TJ (Bill) Ritenour closed off a very well attended meeting - approximately 50 folks turned up!- with an excellent presentation on Printed Wiring Board Design as it pertains to EMC. The  topics covered were Board and Board/Cable resonances, Ground Plane Inductance, The Noise Makers and finally mitigation techniques. Bill started the presentation rather differently first with a list of references and then with a  summary of  old EMC theories as they pertained to board design. He covered switching transients , showed how the radiation from a printed wiring board changes with respect to its width, and compared the measured results with predicted results from a loop formula. Using some excellent handdrawn pictures, Bill then described the concept of board and cable resonances as well as connector ground bounce. We were then presented with the four sources of common-mode current: IC Switching Induced CM current, Capacitor Decoupling Induced CM Current, Transmission Line induced CM current and Connector Induced CM current. Bill then covered Decoupling Capacitors discussing chip cross over current, rise time, capacitor lead inductance, parasitic resonance, series resonance and dynamic impedance.Finally, Bill detailed some printed wiring board practices that can cause EMI and presented mitigation techniques. All in all a very well received presentation - Thanks Bill!!

Download the presentation here

Some pictures from the meeting:

1. EMC Society members enjoy the pizza!! (Bob seems to be emulating Arnold Schwarzenegger?...)

2. The 1999 officers are re-elected. Pictured from left to right are John Stadille (Treasurer), R. Reinert (Secretary), Lyle Luttrell (Chairman) Charles Grasso (Vice-Chair).
Thank you all for your support.

3. Barry kicks off the meeting with some ANSI information.

5. T.J. provides insight into the mysterious ways of EMI and the PWB.

Our thanks to Rich Georgerian for the pictures.