EMC Articles and Papers by Tim Jarvis

Bringing License Free Wireless Products to Market in the EU

This article is the first part of two covering unlicensed wireless products sold and used in the European Union (EU). This article starts with a brief history of wireless regulation as seen from a British perspective. It provides useful background to wireless regulation to those unfamiliar with the topic. The article then proceeds to introduce the recommendations and specifications that govern spectrum use and product approvals for wireless Short Range Devices (SRDs).

Designing to Meet ISO7637 Pulse 5 (Load Dump)

ISO7637 Pulse 5 is a high-energy transient. It’s high energy means that unprotected electronics (ESAs) are usually damaged when exposed to it. In this paper I derive a model for the energy absorption limit of the commonly used 5KP-series (5000 watt) transient suppressors. I then examine alternatives circuits employing Darlington transistors and P-FETs. The advantages and disadvantages of each example circuit are explained.
 
The spreadsheets accompanying this paper can be downloaded individually from here or download bundled as a zip <click here>.

Designing PCBs with RF and EMC issues in mind

Considerable cost savings arise from solving EMC and RF problems on the PCB right from the start of product development.

This presentation for Southern Manufacturing 2007 explains some of the techniques used to control RF emissions and RF immunity at the PCB level. It covers the design of power-planes, PCB layer stack order, the proper use of decoupling capacitors, exploiting ‘free’ parasitic elements to improve filter design and various other techniques (PDF of presentation only).

Designing ESAs to meet PITO5

The Police Information Technology Organisation (PITO) Automotive Conformance Specification 5 places extremely tight constrains on emissions from aftermarket Electronic Sub-Assemblies (ESAs). This paper explains PITO5 testing and conformance requirements and goes on to describe methods for achieving compliance to the radiated emissions requirements using examples the author has worked on.

Joint winner of 'Best Paper' award at the Automotive EMC 2006 conference.

Practical Power Planes for EMC

The physical resonance of power planes within PCBs often negate their advantages. This paper investigates power-plane design both in theory and by practical example.

Winner of 'Best Paper' award at the Automotive EMC 2004 conference.

Integrating Wireless Communications with Microprocessor Based Products

A systematic method for successfully incorporating radio communications modules within processor based electronic products.

IEE New EMC Issues in design, April 2004: conference proceedings

'e' is for Automobile Electronics

Aftermarket electronics products must carry the e-mark, but attaining approval can be confusing for those accustomed to the CE mark.

Compliance Engineering -- 2003 Annual Reference Guide

Telephone Terminal Equipment (TTE) Immunity

The current EU standard for IT & TTE immunity now limits the acceptable demodulated RF interference for telephony products. This article explains the ins-and-outs of designing compliant TTE products.

Compliance Engineering -- November 2001

Eliminating Tetra Interference

Tetra is the European digital standard for PMR and PAMR (radio). Frequency allocations have been shoe-horned in the crowded European spectrum next to low power ISM bands. This article describes Tetra interference and how to avoid it.

Compliance Engineering -- May 2000

EMC Design: Boxing Clever

Some basic concepts in enclosure design for electronics products are discussed. Techniques the author has used effectively in the past are explained. A novel technique known as "capacitive fold coupling" is described.

Approval Magazine -- September 1999

Best Practice in PCB Design

The author goes right back to basics and Maxwell's theory (without the maths). Only with a good basic understanding can a PCB designer go on to apply EMC rules correctly and appropriately.

Approval99 Conference Proceedings

Improving the immunity of sensitive analogue electronics

Of particular relevance to manufacturers seeking to comply with EN55024 (immunity standard). This articles describes basic techniques for producing compliant designs.

UK EMC Journal -- February 1997