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It's probably the economics of FCC/CE testing vs utility. The testing for unintentional radiators is onerous enough. If you add an intentional radiator, you trigger a whole lot more tests and a whole more cost.


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Yet both examples still have to go through FCC testing. Anything digital with a clock over 9 kHz has to go through unintentional radiator testing.

To further point out, the test that caused the incident was not a 'routine test'. They had purposely disabled a large number of safety catches in order to perform a risky and ill-advised test.

The aim of this test was to determine whether cooling of the core could continue to be ensured in the event of a loss of power.


BTLE and WiFi are getting a bit easier thankfully. I know the TI CC3000 doesn't require intentional emitter testing if the recommended design is followed which saves a _lot_ of money and time. [0]

Agreed that FCC unintentional emitter testing can be a pain, however, unless you're doing something very fancy it's not that hard to achieve, and it's not super expensive if you just need a low frequency unintentional testing.

I'm not a lawyer, but I think you can self declare as well for unintentional emitters, just if you get caught the penalties are much stricter than if you can prove you went through a lab.

[0] http://processors.wiki.ti.com/index.php/CC3000_Product_Certi...


Is there a reason they require device specific tests?

It's the "unknowns" not accounted for in the models that are the (potential) issue. If you have time read through this Ars Technica thread where a bunch of these questions are hashed out: http://arstechnica.com/civis/viewtopic.php?f=23&t=116333...

For those without the time, I'll highlight one post from page 5:

"Unintentional radiators.

The reason they ask you to power down ALL electronics, and not just turn off radios, is that the oscillators (the clock that runs all digital devices) on the circuit board can act as miniature radios, in and of themselves, via clock signals on circuit traces. They emit at the clock frequency, and in some cases many higher level harmonics of those frequencies.

As I've stated several times, it's actually pretty easy to mitigate against known frequencies and signalling techniques...it's the ones you don't know about that are the problem. EMI can be downright spooky.

As an example: I was once testing a medical device (for the Medical Device Directive) that was required to failsafe, since it would literally be touching a patient (it was a combination pulseoximeter and a few other things all rolled into one.

There were numerous tests for both emissions and immunity, and things were going along ducky until we noticed two separate failure modes that weren't considered failsafe. At the time, we were testing ESD immunity up to 20kV. It would pass one time, and not another. We thought maybe we had a bad unit, so we got a few more from the manufacturer. That entire week we kept trying to figure out how to make the failure repeatable, without luck. My coworker and I went in over the weekend, and could simply not make any of the units fail at all, with the exact same test.

That's what triggered our thought process...what else could be causing the issue during the work week but not on a weekend?

Other immunity tests! Turns out, a dozen or so meters away, a different device was undergoing a different test...that wasn't required for the MDD. It was a conducted immunity test (it may have been Electric Fast Transients, can't recall) but the actual test signal was leaking out of that lab, and into our lab, via AC lines in the building. Our chief engineer submitted a proposal to add whatever test it was to the MDD, but I don't know whatever became of that.

I've seen simple clocks inside electronic gear cause CPUs to go haywire...in effect a single system interfering with itself. I've also seen extremely low power, yet very high frequency harmonics invade and corrupt function of another device, several meters away."


For me it's basically summed up as "we didn't test turning the power off" and making sure things worked the way we planned.

Yes it is hard and very expensive to do these types of tests. And doing it regularly is even more $$$ and time.

As most customers we seem to be okay with a cheap price hidden behind a facade of "high availability" since I don't really want to pay for true HA. Because if I knew the real cost it would be too expensive.


There's no intent to deceive necessary in the water heater example. The water heater company could have sent it in with a note to the regulator saying "we moved the second element up, because we believe it will perform better on your test" and the regulator would likely just accept it instead of redesigning the test.

Also, for the water heating one, there's a plausible reason for the regulator to care about the discrete measurements rather than the total amount of thermal energy in the water. Hot water at the top of the tank is more valuable, because it's used first and less likely to be wasted, so you could wait it more heavily in a test. There's no parallel for the VW test cheating. No indication that's what happened here, of course.


The flip side of the water heater test is, you could game the test the other way too. Making your water heater look worse than it is. Would you do that? No.

The difference between the water heater and VW is the water heater manufacturer is providing a representative sample. And VW was not. It'd also be dubious to say that the water heater company is acting in bad faith. Where VW's bad faith rose to the level of criminal. On the other hand Volvo appears to be acting in strictly good faith.

Bad faith for a crash test would be crafting a silver plate model for testing. Reminds me that's what my uncle said the power supply manufacturer he worked for did.


System-level testing doesn't always suffice; see the Toyota UA case.

Or, more topically, see the VW case for examples of why testing "in-service-operation-equivalent" requires a certain level of trust that's not ideal in a regulatory relationship.


They probably don't test. Yield is likely high enough that failures are the responsibility of the customer.

There is significant effort (and progress) in standardizing and contrasting test methods [1]. This usually constitues a good first step in a market of lemons. [1] http://energy.gov/sites/prod/files/2014/09/f18/es_cunningham...

Hardware and business process would also need review. Its no good having perfect code if you can insert the wrong sample. It's also no good having perfect code if a well-timed EMI burst or power level shift games the result.

There seems to be a lot here that doesn't pass even a cursory sniff test. Just thinking about the power consumption of the networking equipment involved and doing some quick napkin math should have at least made them suspicious of their results.

EMI testing only tests a product during typical use.

It's very possible to transmit illegal power levels with software mods, or even carefully crafted data packets in some cases.


This has always felt like a concern that is probably just not worth having for the vast majority of folks. With the test finding at best a 5 watt difference, I don't think I'm changing my prior on this any time soon.

I think that kind of test would be more useful on CI hardware that’s usually pretty consistent but it’s a good point to raise.

There's an angle that the company making these didn't think of. That's exactly the kind of critical use case you miss when you don't do enough testing.

Load testing wasn't really relevant here anyways. Even if they load tested their worst case it wouldn't have told them much about 50x that.

To give the tech the benefit of the doubt, it's possible that he just isn't certain he can trust other speed tests. They may point to issues beyond his control.

I wonder how they missed it. If someone was asked to write verification tests for a RTC chip, this would one of the first few things obvious things to be checked.
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