Introduction
Optimize for EMC emission and immunity and don't forget all the others.
A printed circuit board (PCB) normally operates in a 3-dimensional electromagnetic environment. Several cable connections will cross other electromagnetic domains. EMC specialists tend to focus on only one aspect, the EMC validation test, but that’s not how it works. Electronic designs might pass all the EMC validation tests, but still suffer from clock-jitter, self-pollution and software hang-ups. This results in designs that have a low technical performance and are extremely difficult to maintain.
In a professional and demanding world this is not acceptable.
Electronic hardware design
Preventing electronic design self-polution, because it's important!
The picture shows a self-polluted (oversampling) ADC system of 24 bits.
Pollution visible in the FFT noise-floor-spectrum shows two peaks coming up at 50Hz and 300Hz. The 50Hz is the mains frequency leaking into the measurement system, while the 300Hz is caused by self-pollution of the electronics. The 24-bit ADC system is therefore limited to a dynamic range of 20-bits. This is caused by improper PCB design, bad layout and a lack of noise-class-partitioning. Because a total bandwidth of 0-500Hz was required, filtering and further digital processing was not possible. So unfortunately, a redesign using proper noise-class patitioning was necessary.
About me
Jack Leijssen
30+ Years of experience in the field of extreme EMC demanding electronics and PCB designs.
Read the full article in the Bits&Chips.
“The IC designers screwed up and I got to clean up their mess,” recounts Jack. “They failed to adequately separate the analog and digital parts on the chip. Fixing that was not an option as that would have meant that they would have to start all over again. 
I had to look for solutions outside the chip. Moving the power supply, for example. And with all kinds of resistors terminating the transmissionlines, I was able to curb the over and underflow currents, thereby reducing the crossover between the digital nets and improving the signal-to-noise ratio to the analog part. I fixed the IC design screwups on the board level.” With this, he cemented his reputation as an electronic design specialist within Philips. Nowadays Jack is teaching via the High Tech Institute.