Absorption of digital hash

Berkeley uses material to absorb stray digital noise. Anyone know what they use?


@greg_f . In a review of Alpha Reference mention of "material" added to absord radiated digital noise, nothing complicated.

This is the comment from Mr. Harleys' review of the Dac 3. I'd like to know the material.

"When I removed the Alpha 3’s top panel, I noticed a square of material above the digital-to-analog conversion section, just as in the Reference. This ultra-expensive material absorbs and diffuses RF energy. Noise radiated by circuits is absorbed rather than being reflected from the top panel back into the circuit board."



I just don't believe you can slap a little bit of some 'magic' material to tackle emissions. EMC compliance (includes RFI/EMI emissions) is big business in Europe and companies spend millions to ensure their products meet the requirements at all stages of product development.  At the design stage you account for emissions and you control them using various design techniques. Then there are several stages of EMC testing before a product is released to production.

If you believe you have emissions issues you need to measure it and then decide what to do about it. I am assuming that you mean emissions when you say stray digital noise. What do you think is the root of it, where is it coming from?