Went for a meeting to an interesting company today. Cetecom is a big player in the Certification and Testing space. They do EMI and EMC testing, but that is only a small part of what all they do. They do Bluetooth compatibility testing, Wifi Logo Testing, CTIA Converged Wireless testing, 3G, LTE and Audio testing. They gave us a walk through their labs…
When I walked into the building I was expecting EMI/EMC testing…the usual stuff. I learned a lot in my visit. They not only do EMI/EMC testing but they have testing for standards, not only WiFi and BT but for PTCRB CETCOM carrier testing, Antenna performance, network load testing etc. Their 2G/3G testing is done in another lab in San Diego so I did not get to see it. I did see their GSM labs though.
Audio Testing
They have a very complete audio lab. At that lab they are doing audio testing for a lot of cell phone, tablet, headset companies. They have two main labs. One of them is a calibrated sound room, and the other is an Anechoic Audio chamber. Luis gave me a great introduction to the types of devices that they test. The audio tools they were using were from Head Acoustic.
Cellular handsets – a lot of handsets are coming today with dual microphone solutions. The intention for a dual microphone solution is that one mic samples the noise and the other mic gets both noise and speech and the system cancels the noise and sends audio. In their sound room they had a head setup (the head is made up of material similar to skin and bones) and they have a harness that holds up the cell phone close to the ear. In that sound room they are able to simulate different types of noise, loud noises, music etc. The room also can simulate absolute silence. Outside they have their measuring equipment. A call is made from a test system to the cell phone and the audio that comes from the room is recorded in different situations.
A note on testing in complete silence…if you have used the Golden-I headset in a trade show you would have seen how good the system response is, but in complete silence you have to lower your voice so that the system registers the command.
Companies like audience (make noise cancellation chipsets) use their services to compare the different phones that are shipping with those that use their (audience’s) noise cancellation technology. They provide the regular audio tests like MOS Scores (and there is a whole lot of them), they are testing with something called G.160 for things like echo tails and acoustic echo cancellation.
We then went into the Audio anechoic chamber. You just walk in and everything feels different. Silence sounds different and the sound of my own voice feels different. I asked him what is special about an anechoic audio chamber, and for a demo he yelled at the top of his voice. He said that outside the chamber you will always get some reflections of audio so a yell tends to stretch out a bit, but this room has no reflections and so no echo. The yell just stopped. I guess we are always used to have some level of echo. Just being in the room hurt the ears.
While this felt like a lot of audio testing I was reminded of a visit to an Audio ODM in Hong Kong that we had visited in 2006, they have some severe amounts of testing for room equalization, large speaker systems etc.
Wifi Testing
There are multiple labs they showed me for Wifi Testing. One for Wifi compliance, another for Wifi power levels and a third for SARS and radiation levels.
They have separate labs where they are testing wifi devices. They have racks and racks of Wireless devices and they are testing for interoperability, wifi standards. This is not signal quality testing but the testing of whether a wifi device complies with the specification. This is brute force wireless protocol based testing. They do this testing for chipsets and full products.
Something the pointed out to me was that quite often they have customers who have done the development of their design had have RF problems. And sometimes the problems are so big that they need to take the device back to the drawing board. They asked if we have RF experience because they know some RF labs (they named, Connected Development, Spectrum Design, and Device Solutions) but those labs are primarily RF design labs and don’t have digital design experience. They also said that often when somebody comes with a digital design they typically don’t have problems but an analog RF system has a lot of issues.
The RF testing lab was similar to what I have seen before. But they have so many labs in that building. They have separate labs for testing 2G, 3G devices. And more or less every room we went into had an expert on the subject.
Bluetooth testing
Like wifi testing they have labs that more or less do the same thing for Bluetooth testing. But with the acoustics testing that they do there is more to their bluetooth testing. They are able to test the audio quality, direction of audio and a lot more.
SARS Testing
One of the testing items that I had only hear about was SARS testing. This one is the most difficult to describe. The intention of the testing here is to be able to test the radiation from a device and the effect it would have on the body. The room had a robotic arm onto which a device was strapped. The device would be held close to what I will call tubs of fluid. The general shape of the tubs were in the shape of body parts. They had different liquids with different densities. Those that had been measured to replicate the density of the human body. The table itself was a measurement system. The robot moves the device around to different body parts (and turns it into various angles so that emissions from all the different of the device are measured) and measurements are taken. Of course it is cool to watch a robot do its work, but I also got to understand why they use a robot…so that they can do a thorough job of the testing.
The MFI Lab
This is one lab that they did not show us. Pointed out to it and walked on. I smiled to myself…the Apple magic. Basically they test a lot of Made for iPod devices in the lab according to a set of compatibility tests that Apple requires. But they didn’t tell me that. Infact they told me nothing but the fact that it was the MFI lab (Made for iPod/iPhone/iPad).
EMI/EMC lab
This was like any other lab that I have seen so I don’t have much to write about. If you have not seen one it is basically a table on which the test object is placed, and equipment in the Anechoic radio chamber measures emissions from the device on a whole range of RF frequencies. This is a huge room, sufficiently shielded so that there is no outside RF interference.
But in that lab they told me about what some of the Car companies are looking for. Companies like Ford etc are looking for labs where they can drive a car into the lab and they are able to test the product whole. With cars becoming basically BT and WiFi devices themselves (with 3G thrown in for good measure), car companies are looking for ways to test them.
Ideas? recommendations? suggestions? data to add?
Samyeer Metrani 