[sdiy] Advice for selling gear: FCC part 15 certification?

[Magnus Danielson]

From: Grant Richter <grichter at asapnet.net>
Subject: Re: [sdiy] Advice for selling gear: FCC part 15 certification?
Date: Wed, 18 Jun 2003 10:37:13 -0500

> > Wonder what Grant does for his modules.....Hey Grant!
> 
> The analog modules fail the definition of a digital device, therefore part
> 15 is not applicable.
> 
> While a VCO generates pulses over 9 kHz, it doesn't use digital techniques.
> It would be interesting to see a lawyer prove an op-amp is digital.

Actually, it may very well do that. They are not "digital" in the sense of
digital gates, but they never the less have digital properties in the form of
the reset-curcuit and also pulse/PWM-outputs. Your definition of digital may
not necessarilly apply.

However, even if a box isn't digital, it surely goes under some other EMC
regulation, so be carefull!

> There are no crystals, no RF clocks, none of the traditional digital RF
> generators. Pulse edges are a slow (by RF standards) and frequencies are
> very low (by RF standards). Everything is carefully filtered and shielded to
> keep RF out. In analog, bandwidth and slew rate are deliberately limited to
> below RF. This is to keep RF out of the audio signal path, but it has the
> equal effect of suppressing RF radiation out of the analog device.

All good means of controling, but one has to read carefully in the specs. Also,
the CE mark stuff may be quite different.

> You also have to take into consideration the intent of the law. It's
> intended to prevent harmful interference to emergency radio services and
> navigational aids.

Indeed, but also commercial radio use, such as radio and TV broadcasts shall
not be disturbed.

> If there is an FCC complaint, it's the customers
> responsibility to cease operation.
> 
> To my knowledge, none of the 6500 Moog modules or 15,000 Serge modules has
> generated an RF interference complaint.

EMC was not as hot topic then as it is now, so comparision is not really fair.
What used to be OK may actually require checking out these days.

It is a mess, and the safe thing is to read really carefull. Much of what one
needs to know is available online. Only some specs costs money, but most of
that you don't need unless you are really serious.

Cheers,
Magnus